Online - GCeasy GC log analysis tools

1.GCeasy

地址：gceasy

2.Simulate pile out of memory

2.1代码引入

jvm配置

-Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -Xloggc:D:/Desktop/GCLogTest.log

import java.util.ArrayList;

/** * Test generation detailed log file * * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC */
public class GCLogTest {
    
    public static void main(String[] args) {
    
        ArrayList<byte[]> list = new ArrayList<>();

        for (int i = 0; i < 5000; i++) {
    
            byte[] arr = new byte[1024 * 50];//50KB
            list.add(arr);
            try {
    
                Thread.sleep(30);
            } catch (InterruptedException e) {
    
                e.printStackTrace();
            }
        }

    }
}

2.2运行代码生成log文件

2.3上传log文件

3.Simulation of yuan space abnormal

3.1代码引入

JVM配置

 -Xms60m -Xmx60m -XX:MetaspaceSize=10m -XX:MaxMetaspaceSize=10m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -Xloggc:D:/Desktop/MetaspaceOOM.log

import com.sun.xml.internal.ws.org.objectweb.asm.ClassWriter;
import jdk.internal.org.objectweb.asm.Opcodes;

/** * java.lang.OutOfMemoryError: Metaspace异常演示： * * -Xms60m -Xmx60m -XX:MetaspaceSize=10m -XX:MaxMetaspaceSize=10m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC * */
public class MetaspaceOOM extends ClassLoader {
    
    public static void main(String[] args) {
    
        int j = 0;
        try {
    
            MetaspaceOOM test = new MetaspaceOOM();
            for (int i = 0; i < 10000; i++) {
    
                //创建ClassWriter对象,用于生成类的二进制字节码
                ClassWriter classWriter = new ClassWriter(0);
                //指明版本号,修饰符,类名,包名,父类,接口
                classWriter.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC, "Class" + i, null, "java/lang/Object", null);
                //返回byte[]
                byte[] code = classWriter.toByteArray();
                //类的加载
                test.defineClass("Class" + i, code, 0, code.length);//Class对象
                j++;
            }
        } finally {
    
            System.out.println(j);
        }
    }
}

3.2运行代码生成log文件

3.3上传log文件