逃逸分析-锁消除-栈上分配例子

作者: wuli白 | 来源:发表于2020-04-09 16:10 被阅读0次

/**
 * 开启逃逸分析：-XX:+DoEscapeAnalysis
 * 关闭逃逸分析：-XX:-DoEscapeAnalysis
 * -XX:+EliminateLocks开启锁消除（jdk1.8默认开启，其它版本未测试）
 * -XX:-EliminateLocks 关闭锁消除
 **/
public class Main {

    public static void main(String[] args) {
        long start = System.currentTimeMillis();
        for (int i = 0; i < 5000000; i++) {
            alloc();
            lock("TestLockEliminate ", "Suffix");
        }
        long end = System.currentTimeMillis();
        System.out.println(end - start);



    }

    public static String lock(String s1, String s2) {
        StringBuffer sb = new StringBuffer();
        sb.append(s1);
        sb.append(s2);
        return sb.toString();
    }

    /**
     * 栈上分配
     */
    private static void alloc() {
        User user = new User();
        user.setName("a");
    }


    @Data
    static class User {
        private String name;
        private String age;
    }
}