JavaOOM

StackOverFlowError

public class StackOverFlowErrorDemo {

    public static void main(String[] args) {
        dfs();//Exception in thread "main" java.lang.StackOverflowError
    }

    public static void dfs(){
        dfs();
    }
}

最常见在递归中无返回条件一直调用。

JavaHeapSpace

public class JavaHeapSpaceDemo {

    public static void main(String[] args) {
        String str="wqoierihfsdkfsdf";

        while (true){
            str+=new Random().nextInt(108432432)+new Random().nextInt(238923293);
            str.intern();
        }
    }
}

GC Overhead Limited Exceeded

/**-Xms10m -Xmx10m -XX:+PrintGCDetails -XX:MaxDirectMemorySize=3m
 * @author xixing
 * @version 1.0
 * @date 2020/7/27 15:33
 */
public class GCOverheadDemo {

    public static void main(String[] args) {
        int i=0;

        List<String> list=new ArrayList<>();

        try {
            while (true){
                list.add(String.valueOf(i++).intern());
            }
        }catch (Throwable e){

            System.out.println("********************");
            System.out.println(i);
            e.printStackTrace();

        }
    }
}

DirectBufferMemory

/**
 * @author xixing
 * @version 1.0
 * @date 2020/7/27 15:49
 */
public class DirectBufferMemoryDemo {
    public static void main(String[] args) {


        System.out.println("配置的本地内存maxDirectMemory:"+sun.misc.VM.maxDirectMemory()/(double)1024/1024+"MB");
        Buffer bb= ByteBuffer.allocateDirect(10*1024*1024);
    }
}

Unable to create new native thread

/**
 * @author xixing
 * @version 1.0
 * @date 2020/7/27 16:08
 */
public class UnableCreateNewThreadDemo {
    public static void main(String[] args) {

        for (int i = 0; ; i++) {
            System.out.println("****************"+i);
            new Thread(()->{
                try {
                    Thread.sleep(Integer.MAX_VALUE);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            },String.valueOf(i)).start();
        }

    }
}

调整最大线程数

ulimit -u 查看可以创建的最大线程

vim /etc/security/limits.d/90-nproc.conf

Metaspace