周末了，覺得我還有很多作業沒有寫，針對目前大家對OOM的類型不太熟悉，那么我們來總結一下各種OOM出現的情況以及解決方法。

我們把各種OOM的情況列出來，然后逐一進行代碼編寫復現和提供解決方法。

1. 堆溢出-java.lang.OutOfMemoryError: Java heap space。

2. 棧溢出-java.lang.OutOfMemorryError。

3. 棧溢出-java.lang.StackOverFlowError。

4. 元信息溢出-java.lang.OutOfMemoryError: Metaspace。

5. 直接內存溢出-java.lang.OutOfMemoryError: Direct buffer memory。

6. GC超限-java.lang.OutOfMemoryError: GC overhead limit exceeded。

第一種，堆溢出異常，相信大家很常見。即堆內對象不能進行回收了，堆內存持續增大，這樣達到了堆內存的最大值，數據滿了，所以就出來了。我們直接放溢出的代碼樣例。我們需要設置好idea的VM Options: -Xmx100m，這樣我們設置為最大堆內存，這樣運行起來就很快就出來錯誤了。

package oom;import java.util.ArrayList;import java.util.List;import java.util.concurrent.TimeUnit;/** * @author huangqingshi * @Date 2020-07-18 */public class HeapOOM { static class OOMObject { } public static void main(String[] args) throws InterruptedException { List<OOMObject> list = new ArrayList<>(); while(true) {// TimeUnit.MILLISECONDS.sleep(1); list.add(new OOMObject()); } }}

運行的異常如下，代碼直接就出來我們看到的異常了。

/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/bin/java -Xmx100m -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/tools.jar:/Users/huangqingshi/Downloads/flink-project/target/classes:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-java/1.7.2/flink-java-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-core/1.7.2/flink-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-annotations/1.7.2/flink-annotations-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-metrics-core/1.7.2/flink-metrics-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/kryo/kryo/2.24.0/kryo-2.24.0.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/minlog/minlog/1.2/minlog-1.2.jar:/Users/huangqingshi/.m2/repository/org/objenesis/objenesis/2.1/objenesis-2.1.jar:/Users/huangqingshi/.m2/repository/commons-collections/commons-collections/3.2.2/commons-collections-3.2.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-compress/1.18/commons-compress-1.18.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-asm/5.0.4-5.0/flink-shaded-asm-5.0.4-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-lang3/3.3.2/commons-lang3-3.3.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-math3/3.5/commons-math3-3.5.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-api/1.7.15/slf4j-api-1.7.15.jar:/Users/huangqingshi/.m2/repository/com/google/code/findbugs/jsr305/1.3.9/jsr305-1.3.9.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/force-shading/1.7.2/force-shading-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-streaming-java_2.11/1.7.2/flink-streaming-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-runtime_2.11/1.7.2/flink-runtime_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-queryable-state-client-java_2.11/1.7.2/flink-queryable-state-client-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-hadoop-fs/1.7.2/flink-hadoop-fs-1.7.2.jar:/Users/huangqingshi/.m2/repository/commons-io/commons-io/2.4/commons-io-2.4.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-netty/4.1.24.Final-5.0/flink-shaded-netty-4.1.24.Final-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-jackson/2.7.9-5.0/flink-shaded-jackson-2.7.9-5.0.jar:/Users/huangqingshi/.m2/repository/commons-cli/commons-cli/1.3.1/commons-cli-1.3.1.jar:/Users/huangqingshi/.m2/repository/org/javassist/javassist/3.19.0-GA/javassist-3.19.0-GA.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/scala-library/2.11.12/scala-library-2.11.12.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-actor_2.11/2.4.20/akka-actor_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/com/typesafe/config/1.3.0/config-1.3.0.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/modules/scala-java8-compat_2.11/0.7.0/scala-java8-compat_2.11-0.7.0.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-stream_2.11/2.4.20/akka-stream_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/org/reactivestreams/reactive-streams/1.0.0/reactive-streams-1.0.0.jar:/Users/huangqingshi/.m2/repository/com/typesafe/ssl-config-core_2.11/0.2.1/ssl-config-core_2.11-0.2.1.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/modules/scala-parser-combinators_2.11/1.0.4/scala-parser-combinators_2.11-1.0.4.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-protobuf_2.11/2.4.20/akka-protobuf_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-slf4j_2.11/2.4.20/akka-slf4j_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/org/clapper/grizzled-slf4j_2.11/1.3.2/grizzled-slf4j_2.11-1.3.2.jar:/Users/huangqingshi/.m2/repository/com/github/scopt/scopt_2.11/3.5.0/scopt_2.11-3.5.0.jar:/Users/huangqingshi/.m2/repository/org/xerial/snappy/snappy-java/1.1.4/snappy-java-1.1.4.jar:/Users/huangqingshi/.m2/repository/com/twitter/chill_2.11/0.7.6/chill_2.11-0.7.6.jar:/Users/huangqingshi/.m2/repository/com/twitter/chill-java/0.7.6/chill-java-0.7.6.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-clients_2.11/1.7.2/flink-clients_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-optimizer_2.11/1.7.2/flink-optimizer_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-guava/18.0-5.0/flink-shaded-guava-18.0-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-connector-kafka-0.10_2.11/1.7.2/flink-connector-kafka-0.10_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-connector-kafka-0.9_2.11/1.7.2/flink-connector-kafka-0.9_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-connector-kafka-base_2.11/1.7.2/flink-connector-kafka-base_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/kafka/kafka-clients/0.10.2.1/kafka-clients-0.10.2.1.jar:/Users/huangqingshi/.m2/repository/net/jpountz/lz4/lz4/1.3.0/lz4-1.3.0.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-log4j12/1.7.7/slf4j-log4j12-1.7.7.jar:/Users/huangqingshi/.m2/repository/log4j/log4j/1.2.17/log4j-1.2.17.jar:/Users/huangqingshi/.m2/repository/com/alibaba/fastjson/1.2.62/fastjson-1.2.62.jar:/Users/huangqingshi/.m2/repository/com/google/guava/guava/28.1-jre/guava-28.1-jre.jar:/Users/huangqingshi/.m2/repository/com/google/guava/failureaccess/1.0.1/failureaccess-1.0.1.jar:/Users/huangqingshi/.m2/repository/com/google/guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:/Users/huangqingshi/.m2/repository/org/checkerframework/checker-qual/2.8.1/checker-qual-2.8.1.jar:/Users/huangqingshi/.m2/repository/com/google/errorprone/error_prone_annotations/2.3.2/error_prone_annotations-2.3.2.jar:/Users/huangqingshi/.m2/repository/com/google/j2objc/j2objc-annotations/1.3/j2objc-annotations-1.3.jar:/Users/huangqingshi/.m2/repository/org/codehaus/mojo/animal-sniffer-annotations/1.18/animal-sniffer-annotations-1.18.jar:/Users/huangqingshi/.m2/repository/redis/clients/jedis/3.1.0/jedis-3.1.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-pool2/2.6.2/commons-pool2-2.6.2.jar:/Users/huangqingshi/.m2/repository/mysql/mysql-connector-java/8.0.16/mysql-connector-java-8.0.16.jar:/Users/huangqingshi/.m2/repository/com/google/protobuf/protobuf-java/3.6.1/protobuf-java-3.6.1.jar:/Users/huangqingshi/.m2/repository/com/alibaba/druid/1.1.20/druid-1.1.20.jar oom.HeapOOMException in thread 'main' java.lang.OutOfMemoryError: Java heap space at java.util.Arrays.copyOf(Arrays.java:3210) at java.util.Arrays.copyOf(Arrays.java:3181) at java.util.ArrayList.grow(ArrayList.java:261) at java.util.ArrayList.ensureExplicitCapacity(ArrayList.java:235) at java.util.ArrayList.ensureCapacityInternal(ArrayList.java:227) at java.util.ArrayList.add(ArrayList.java:458) at oom.HeapOOM.main(HeapOOM.java:21)

Process finished with exit code 1

細心的同學可以發現我在里邊設置了一個休眠，目的是我們看一下堆內存的結構和數據圖。我們將休眠代碼打開，然后打開JDK自帶的jconsole命令，連接上之后我們看一下概覽圖，通過下圖我們發現堆內存持續不斷的增長。

我們打開內存界面，看一下內存，然后點一下GC按鈕，這個時候會有一些類進行回收，但是還是會繼續增長，看一下下面的圖。

點開信息標簽看一下。經過幾次GC回收之后，類的數據量還是變化不大，說明沒有進行回收。

以上這種情況的解決方法就是找到問題點，分析哪個地方是否存儲了大量類沒有被回收的情況，通過JMAP命令將線上的堆內存導出來后進行分析。

第二種情況，我們看一下棧溢出的情況，“上菜”，下面的代碼就是無限的創建線程，直到沒法再創建線程。

package oom;import java.util.concurrent.TimeUnit;/** * @author huangqingshi * @Date 2020-07-18 */public class StackOOM { public static void infiniteRun() { while(true) { Thread thread = new Thread(() -> { while (true) { try { TimeUnit.HOURS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); } } }); thread.start(); } } public static void main(String[] args) { infiniteRun(); }}

拋出來的異常如下，如果真的需要創建線程，我們需要調整幀棧的大小-Xss512k，默認幀棧大小為1M，如果設置小了，可以創建更多線程。

/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/bin/java -Xss512k -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/tools.jar:/Users/huangqingshi/Downloads/flink-project/target/classes:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-java/1.7.2/flink-java-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-core/1.7.2/flink-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-annotations/1.7.2/flink-annotations-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-metrics-core/1.7.2/flink-metrics-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/kryo/kryo/2.24.0/kryo-2.24.0.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/minlog/minlog/1.2/minlog-1.2.jar:/Users/huangqingshi/.m2/repository/org/objenesis/objenesis/2.1/objenesis-2.1.jar:/Users/huangqingshi/.m2/repository/commons-collections/commons-collections/3.2.2/commons-collections-3.2.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-compress/1.18/commons-compress-1.18.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-asm/5.0.4-5.0/flink-shaded-asm-5.0.4-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-lang3/3.3.2/commons-lang3-3.3.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-math3/3.5/commons-math3-3.5.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-api/1.7.15/slf4j-api-1.7.15.jar:/Users/huangqingshi/.m2/repository/com/google/code/findbugs/jsr305/1.3.9/jsr305-1.3.9.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/force-shading/1.7.2/force-shading-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-streaming-java_2.11/1.7.2/flink-streaming-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-runtime_2.11/1.7.2/flink-runtime_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-queryable-state-client-java_2.11/1.7.2/flink-queryable-state-client-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-hadoop-fs/1.7.2/flink-hadoop-fs-1.7.2.jar:/Users/huangqingshi/.m2/repository/commons-io/commons-io/2.4/commons-io-2.4.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-netty/4.1.24.Final-5.0/flink-shaded-netty-4.1.24.Final-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-jackson/2.7.9-5.0/flink-shaded-jackson-2.7.9-5.0.jar:/Users/huangqingshi/.m2/repository/commons-cli/commons-cli/1.3.1/commons-cli-1.3.1.jar:/Users/huangqingshi/.m2/repository/org/javassist/javassist/3.19.0-GA/javassist-3.19.0-GA.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/scala-library/2.11.12/scala-library-2.11.12.jar:/Users/huangqingshi/.m2/repository/com/type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oom.StackOOMException in thread 'main' java.lang.OutOfMemoryError: unable to create new native thread at java.lang.Thread.start0(Native Method) at java.lang.Thread.start(Thread.java:717) at oom.StackOOM.infiniteRun(StackOOM.java:24) at oom.StackOOM.main(StackOOM.java:29)

Process finished with exit code 130 (interrupted by signal 2: SIGINT)

以上這種情況是幀棧不夠用了，如果出現了這種情況，我們需要了解什么地方創建了很多線程，線上程序需要用jstack命令，將當前線程的狀態導出來放到文件里邊，然后將文件上傳到fastthread.io網站上進行分析。

第三種情況，我們看一下棧溢出的另一種情況，這就是棧的StackOverFlow的情況。下面就是一個死循環遞歸調用。

package oom;/** * @author huangqingshi * @Date 2020-07-18 */public class StackOFE { public static void stackOverFlowErrorMethod() { stackOverFlowErrorMethod(); } public static void main(String[] args) { stackOverFlowErrorMethod(); }}

運行之后出現的錯誤如下，程序每次遞歸的時候，程序會把數據結果壓入棧，包括里邊的指針等，這個時候就需要幀棧大一些才能承受住更多的遞歸調用。通過-Xss進行設置，上邊的例子需要設置小一些，以分配更多的幀棧，這次是一個幀棧需要記錄程序數據，所以需要更大的值。

/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/bin/java -Xss2m -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/tools.jar:/Users/huangqingshi/Downloads/flink-project/target/classes:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-java/1.7.2/flink-java-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-core/1.7.2/flink-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-annotations/1.7.2/flink-annotations-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-metrics-core/1.7.2/flink-metrics-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/kryo/kryo/2.24.0/kryo-2.24.0.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/minlog/minlog/1.2/minlog-1.2.jar:/Users/huangqingshi/.m2/repository/org/objenesis/objenesis/2.1/objenesis-2.1.jar:/Users/huangqingshi/.m2/repository/commons-collections/commons-collections/3.2.2/commons-collections-3.2.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-compress/1.18/commons-compress-1.18.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-asm/5.0.4-5.0/flink-shaded-asm-5.0.4-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-lang3/3.3.2/commons-lang3-3.3.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-math3/3.5/commons-math3-3.5.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-api/1.7.15/slf4j-api-1.7.15.jar:/Users/huangqingshi/.m2/repository/com/google/code/findbugs/jsr305/1.3.9/jsr305-1.3.9.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/force-shading/1.7.2/force-shading-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-streaming-java_2.11/1.7.2/flink-streaming-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-runtime_2.11/1.7.2/flink-runtime_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-queryable-state-client-java_2.11/1.7.2/flink-queryable-state-client-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-hadoop-fs/1.7.2/flink-hadoop-fs-1.7.2.jar:/Users/huangqingshi/.m2/repository/commons-io/commons-io/2.4/commons-io-2.4.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-netty/4.1.24.Final-5.0/flink-shaded-netty-4.1.24.Final-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-jackson/2.7.9-5.0/flink-shaded-jackson-2.7.9-5.0.jar:/Users/huangqingshi/.m2/repository/commons-cli/commons-cli/1.3.1/commons-cli-1.3.1.jar:/Users/huangqingshi/.m2/repository/org/javassist/javassist/3.19.0-GA/javassist-3.19.0-GA.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/scala-library/2.11.12/scala-library-2.11.12.jar:/Users/huangqingshi/.m2/repository/com/type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oom.StackOFEException in thread 'main' java.lang.StackOverflowError at oom.StackOFE.stackOverFlowErrorMethod(StackOFE.java:10) at oom.StackOFE.stackOverFlowErrorMethod(StackOFE.java:10) at oom.StackOFE.stackOverFlowErrorMethod(StackOFE.java:10) at oom.StackOFE.stackOverFlowErrorMethod(StackOFE.java:10) at oom.StackOFE.stackOverFlowErrorMethod(StackOFE.java:10) at oom.StackOFE.stackOverFlowErrorMethod(StackOFE.java:10)

遇到上面的情況下，那么就需要通過jstack將線程數據導到文件進行分析。找到遞歸的點，如果程序就是需要遞歸的次數的話，那么這個時候就需要增大幀棧的大小以適應程序。

第四種情況，元數據區域溢出，元數據區域也成為方法區，存儲著類的相關信息，常量池，方法描述符，字段描述符，運行時產生大量的類就會造成這個區域的溢出。我們運行的時候指定一下元數據區域的大小，設置到idea的VM options里邊：-XX:MetaspaceSize=10M -XX:MaxMetaspaceSize=30M。

package oom;import net.sf.cglib.proxy.Enhancer;import net.sf.cglib.proxy.MethodInterceptor;import net.sf.cglib.proxy.MethodProxy;import java.lang.reflect.Method;/** * @author huangqingshi * @Date 2020-07-18 */public class MetaspaceOOM { static class OOMObject{} public static void main(String[] args) { while (true) { Enhancer enhancer = new Enhancer(); enhancer.setSuperclass(OOMObject.class); enhancer.setUseCache(false); enhancer.setCallback(new MethodInterceptor() {public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { return proxy.invokeSuper(obj, args);} }); enhancer.create(); } }}

運行的結果如下，元數據信息溢出了。這種情況產生的原因有： 通過CBLIG大量生成類，導致Meta信息滿了；JDK7的時候使用String.intern()不當，會產生大量常量數據；加載大量的jsp以及動態生成jsp文件。我們需要調整元數據空間的大小，如果調大了之后還出現了這種異常，我們需要分析哪里出現的溢出并fix掉。

/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/bin/java -XX:MetaspaceSize=10M -XX:MaxMetaspaceSize=30M -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/tools.jar:/Users/huangqingshi/Downloads/flink-project/target/classes:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-java/1.7.2/flink-java-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-core/1.7.2/flink-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-annotations/1.7.2/flink-annotations-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-metrics-core/1.7.2/flink-metrics-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/kryo/kryo/2.24.0/kryo-2.24.0.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/minlog/minlog/1.2/minlog-1.2.jar:/Users/huangqingshi/.m2/repository/org/objenesis/objenesis/2.1/objenesis-2.1.jar:/Users/huangqingshi/.m2/repository/commons-collections/commons-collections/3.2.2/commons-collections-3.2.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-compress/1.18/commons-compress-1.18.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-asm/5.0.4-5.0/flink-shaded-asm-5.0.4-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-lang3/3.3.2/commons-lang3-3.3.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-math3/3.5/commons-math3-3.5.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-api/1.7.15/slf4j-api-1.7.15.jar:/Users/huangqingshi/.m2/repository/com/google/code/findbugs/jsr305/1.3.9/jsr305-1.3.9.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/force-shading/1.7.2/force-shading-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-streaming-java_2.11/1.7.2/flink-streaming-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-runtime_2.11/1.7.2/flink-runtime_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-queryable-state-client-java_2.11/1.7.2/flink-queryable-state-client-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-hadoop-fs/1.7.2/flink-hadoop-fs-1.7.2.jar:/Users/huangqingshi/.m2/repository/commons-io/commons-io/2.4/commons-io-2.4.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-netty/4.1.24.Final-5.0/flink-shaded-netty-4.1.24.Final-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-jackson/2.7.9-5.0/flink-shaded-jackson-2.7.9-5.0.jar:/Users/huangqingshi/.m2/repository/commons-cli/commons-cli/1.3.1/commons-cli-1.3.1.jar:/Users/huangqingshi/.m2/repository/org/javassist/javassist/3.19.0-GA/javassist-3.19.0-GA.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/scala-library/2.11.12/scala-library-2.11.12.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-actor_2.11/2.4.20/akka-actor_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/com/typesafe/config/1.3.0/config-1.3.0.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/modules/scala-java8-compat_2.11/0.7.0/scala-java8-compat_2.11-0.7.0.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-stream_2.11/2.4.20/akka-stream_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/org/reactivestreams/reactive-streams/1.0.0/reactive-streams-1.0.0.jar:/Users/huangqingshi/.m2/repository/com/typesafe/ssl-config-core_2.11/0.2.1/ssl-config-core_2.11-0.2.1.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/modules/scala-parser-combinators_2.11/1.0.4/scala-parser-combinators_2.11-1.0.4.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-protobuf_2.11/2.4.20/akka-protobuf_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/com/typesafe/akka/akka-slf4j_2.11/2.4.20/akka-slf4j_2.11-2.4.20.jar:/Users/huangqingshi/.m2/repository/org/clapper/grizzled-slf4j_2.11/1.3.2/grizzled-slf4j_2.11-1.3.2.jar:/Users/huangqingshi/.m2/repository/com/github/scopt/scopt_2.11/3.5.0/scopt_2.11-3.5.0.jar:/Users/huangqingshi/.m2/repository/org/xerial/snappy/snappy-java/1.1.4/snappy-java-1.1.4.jar:/Users/huangqingshi/.m2/repository/com/twitter/chill_2.11/0.7.6/chill_2.11-0.7.6.jar:/Users/huangqingshi/.m2/repository/com/twitter/chill-java/0.7.6/chill-java-0.7.6.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-clients_2.11/1.7.2/flink-clients_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-optimizer_2.11/1.7.2/flink-optimizer_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-guava/18.0-5.0/flink-shaded-guava-18.0-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-connector-kafka-0.10_2.11/1.7.2/flink-connector-kafka-0.10_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-connector-kafka-0.9_2.11/1.7.2/flink-connector-kafka-0.9_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-connector-kafka-base_2.11/1.7.2/flink-connector-kafka-base_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/kafka/kafka-clients/0.10.2.1/kafka-clients-0.10.2.1.jar:/Users/huangqingshi/.m2/repository/net/jpountz/lz4/lz4/1.3.0/lz4-1.3.0.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-log4j12/1.7.7/slf4j-log4j12-1.7.7.jar:/Users/huangqingshi/.m2/repository/log4j/log4j/1.2.17/log4j-1.2.17.jar:/Users/huangqingshi/.m2/repository/com/alibaba/fastjson/1.2.62/fastjson-1.2.62.jar:/Users/huangqingshi/.m2/repository/com/google/guava/guava/28.1-jre/guava-28.1-jre.jar:/Users/huangqingshi/.m2/repository/com/google/guava/failureaccess/1.0.1/failureaccess-1.0.1.jar:/Users/huangqingshi/.m2/repository/com/google/guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:/Users/huangqingshi/.m2/repository/org/checkerframework/checker-qual/2.8.1/checker-qual-2.8.1.jar:/Users/huangqingshi/.m2/repository/com/google/errorprone/error_prone_annotations/2.3.2/error_prone_annotations-2.3.2.jar:/Users/huangqingshi/.m2/repository/com/google/j2objc/j2objc-annotations/1.3/j2objc-annotations-1.3.jar:/Users/huangqingshi/.m2/repository/org/codehaus/mojo/animal-sniffer-annotations/1.18/animal-sniffer-annotations-1.18.jar:/Users/huangqingshi/.m2/repository/redis/clients/jedis/3.1.0/jedis-3.1.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-pool2/2.6.2/commons-pool2-2.6.2.jar:/Users/huangqingshi/.m2/repository/mysql/mysql-connector-java/8.0.16/mysql-connector-java-8.0.16.jar:/Users/huangqingshi/.m2/repository/com/google/protobuf/protobuf-java/3.6.1/protobuf-java-3.6.1.jar:/Users/huangqingshi/.m2/repository/com/alibaba/druid/1.1.20/druid-1.1.20.jar:/Users/huangqingshi/.m2/repository/cglib/cglib/3.2.5/cglib-3.2.5.jar:/Users/huangqingshi/.m2/repository/org/ow2/asm/asm/5.2/asm-5.2.jar:/Users/huangqingshi/.m2/repository/org/apache/ant/ant/1.9.6/ant-1.9.6.jar:/Users/huangqingshi/.m2/repository/org/apache/ant/ant-launcher/1.9.6/ant-launcher-1.9.6.jar oom.MetaspaceOOMException in thread 'main' java.lang.OutOfMemoryError: Metaspace at net.sf.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:345) at net.sf.cglib.proxy.Enhancer.generate(Enhancer.java:492) at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:114) at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:291) at net.sf.cglib.proxy.Enhancer.createHelper(Enhancer.java:480) at net.sf.cglib.proxy.Enhancer.create(Enhancer.java:305) at oom.MetaspaceOOM.main(MetaspaceOOM.java:28)

Process finished with exit code 1

第五種情況，直接內存溢出，我們除了使用堆內存外，我們還可能用直接內存，即堆外內存。NIO為了提高性能，避免在Java Heap和native Heap中切換，所以使用直接內存，默認情況下，直接內存的大小和對內存大小一致。堆外內存不受JVM的限制，但是受制于機器整體內存的大小限制。如下代碼設置堆最大內存為128m，直接內存為100m，然后我們每次分配1M放到list里邊。

-Xmx128m -XX:MaxDirectMemorySize=100Mpackage oom;import java.nio.ByteBuffer;import java.util.ArrayList;import java.util.List;/** * @author huangqingshi * @Date 2020-07-18 */public class DirectBufferOOM { public static void main(String[] args) { final int _1M = 1024 * 1024 * 1; List<ByteBuffer> buffers = new ArrayList<>(); int count = 1; while (true) { ByteBuffer byteBuffer = ByteBuffer.allocateDirect(_1M); buffers.add(byteBuffer); System.out.println(count++); } }}

這個時候，當輸出100次的時候，下次再分配的時候會報OOM-Direct buffer memory。

/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/bin/java -Xmx128m -XX:MaxDirectMemorySize=100M -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jaccess.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/lib/tools.jar:/Users/huangqingshi/Downloads/flink-project/target/classes:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-java/1.7.2/flink-java-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-core/1.7.2/flink-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-annotations/1.7.2/flink-annotations-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-metrics-core/1.7.2/flink-metrics-core-1.7.2.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/kryo/kryo/2.24.0/kryo-2.24.0.jar:/Users/huangqingshi/.m2/repository/com/esotericsoftware/minlog/minlog/1.2/minlog-1.2.jar:/Users/huangqingshi/.m2/repository/org/objenesis/objenesis/2.1/objenesis-2.1.jar:/Users/huangqingshi/.m2/repository/commons-collections/commons-collections/3.2.2/commons-collections-3.2.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-compress/1.18/commons-compress-1.18.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-asm/5.0.4-5.0/flink-shaded-asm-5.0.4-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-lang3/3.3.2/commons-lang3-3.3.2.jar:/Users/huangqingshi/.m2/repository/org/apache/commons/commons-math3/3.5/commons-math3-3.5.jar:/Users/huangqingshi/.m2/repository/org/slf4j/slf4j-api/1.7.15/slf4j-api-1.7.15.jar:/Users/huangqingshi/.m2/repository/com/google/code/findbugs/jsr305/1.3.9/jsr305-1.3.9.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/force-shading/1.7.2/force-shading-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-streaming-java_2.11/1.7.2/flink-streaming-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-runtime_2.11/1.7.2/flink-runtime_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-queryable-state-client-java_2.11/1.7.2/flink-queryable-state-client-java_2.11-1.7.2.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-hadoop-fs/1.7.2/flink-hadoop-fs-1.7.2.jar:/Users/huangqingshi/.m2/repository/commons-io/commons-io/2.4/commons-io-2.4.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-netty/4.1.24.Final-5.0/flink-shaded-netty-4.1.24.Final-5.0.jar:/Users/huangqingshi/.m2/repository/org/apache/flink/flink-shaded-jackson/2.7.9-5.0/flink-shaded-jackson-2.7.9-5.0.jar:/Users/huangqingshi/.m2/repository/commons-cli/commons-cli/1.3.1/commons-cli-1.3.1.jar:/Users/huangqingshi/.m2/repository/org/javassist/javassist/3.19.0-GA/javassist-3.19.0-GA.jar:/Users/huangqingshi/.m2/repository/org/scala-lang/scala-library/2.11.12/scala-library-2.11.12.jar:/Users/huangqingshi/.m2/repository/com/type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oom.DirectBufferOOM123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100Exception in thread 'main' java.lang.OutOfMemoryError: Direct buffer memory at java.nio.Bits.reserveMemory(Bits.java:694) at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:123) at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:311) at oom.DirectBufferOOM.main(DirectBufferOOM.java:18)

Process finished with exit code 1

這種情況是我們使用直接內存造成溢出，這個時候我們需要檢查一下程序里邊是否使用的NIO及NIO，比如Netty，里邊的直接內存的配置。

第6種情況，JDK1.6之后新增了一個錯誤類型，如果堆內存太小的時候會報這個錯誤。如果98%的GC的時候回收不到2%的時候會報這個錯誤，也就是最小最大內存出現了問題的時候會報這個錯誤。如果代碼配置了最小最大堆內存都為10m。

-Xmx10m -Xms10mpackage oom;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;/** * @author huangqingshi * @Date 2020-07-18 */public class GCOverheadOOM { public static void main(String[] args) { ExecutorService executor = Executors.newFixedThreadPool(5); for (int i = 0; i < Integer.MAX_VALUE; i++) { executor.execute(() -> {try { Thread.sleep(10000);} catch (InterruptedException e) { //do nothing} }); } }}

這個我們創建了一個線程池，如果線程池執行的時候如果核心線程處理不過來的時候會把數據放到LinkedBlockingQueue里邊，也就是堆內存當中。這個時候我們需要檢查-Xms -Xmx最小最大堆配置是否合理。再一個dump出現當前內存來分析一下是否使用了大量的循環或使用大量內存代碼。

以上就是我們經常遇到的情況，我們需要針對出現的不行情況進行分析和處理。

總結

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