jol-core

分析对象布局工具
加锁与不加锁能看出区别

pom.xml中加入
<!-- https://mvnrepository.com/artifact/org.openjdk.jol/jol-core -->
<dependency>
    <groupId>org.openjdk.jol</groupId>
    <artifactId>jol-core</artifactId>
    <version>0.16</version>
    <scope>provided</scope>
</dependency>

       TT t = new TT();
        String s = ClassLayout.parseInstance(t).toPrintable();
        System.out.println(s);

        synchronized (t) {
            System.out.println(ClassLayout.parseInstance(t).toPrintable());
        }


com.example.demospringboot.test.ParseClassApp$TT object internals:
OFF  SZ   TYPE DESCRIPTION               VALUE
  0   8        (object header: mark)     0x0000000000000001 (non-biasable; age: 0)
  8   4        (object header: class)    0xf800c143
 12   4    int TT.m                      0
Instance size: 16 bytes
Space losses: 0 bytes internal + 0 bytes external = 0 bytes total

com.example.demospringboot.test.ParseClassApp$TT object internals:
OFF  SZ   TYPE DESCRIPTION               VALUE
  0   8        (object header: mark)     0x0000009f57fff1c0 (thin lock: 0x0000009f57fff1c0)
  8   4        (object header: class)    0xf800c143
 12   4    int TT.m                      0
Instance size: 16 bytes
Space losses: 0 bytes internal + 0 bytes external = 0 bytes total


Process finished with exit code 0