[JVM] 应用诊断工具之javac命令

千千寰宇 / 2024-09-25 / 原文

0 引言

1 JDK命令： javac

反编译指定类: `javac -c {className}`

参考命令 : C:\Users\xxxxxx> javap -c java.lang.Object > "Object.txt"

C:\Users\xxxxxx> javap -c java.lang.Object
Compiled from "Object.java"
public class java.lang.Object {
  public java.lang.Object();
    Code:
       0: return

  public final native java.lang.Class<?> getClass();

  public native int hashCode();

  public boolean equals(java.lang.Object);
    Code:
       0: aload_0
       1: aload_1
       2: if_acmpne     9
       5: iconst_1
       6: goto          10
       9: iconst_0
      10: ireturn

  protected native java.lang.Object clone() throws java.lang.CloneNotSupportedException;

  public java.lang.String toString();
    Code:
       0: new           #52                 // class java/lang/StringBuilder
       3: dup
       4: invokespecial #74                 // Method java/lang/StringBuilder."<init>":()V
       7: aload_0
       8: invokevirtual #73                 // Method getClass:()Ljava/lang/Class;
      11: invokevirtual #67                 // Method java/lang/Class.getName:()Ljava/lang/String;
      14: invokevirtual #76                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      17: ldc           #2                  // String @
      19: invokevirtual #76                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      22: aload_0
      23: invokevirtual #70                 // Method hashCode:()I
      26: invokestatic  #69                 // Method java/lang/Integer.toHexString:(I)Ljava/lang/String;
      29: invokevirtual #76                 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      32: invokevirtual #75                 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      35: areturn

  public final native void notify();

  public final native void notifyAll();

  public final native void wait(long) throws java.lang.InterruptedException;

  public final void wait(long, int) throws java.lang.InterruptedException;
    Code:
       0: lload_1
       1: lconst_0
       2: lcmp
       3: ifge          16
       6: new           #48                 // class java/lang/IllegalArgumentException
       9: dup
      10: ldc           #4                  // String timeout value is negative
      12: invokespecial #68                 // Method java/lang/IllegalArgumentException."<init>":(Ljava/lang/String;)V
      15: athrow
      16: iload_3
      17: iflt          26
      20: iload_3
      21: ldc           #1                  // int 999999
      23: if_icmple     36
      26: new           #48                 // class java/lang/IllegalArgumentException
      29: dup
      30: ldc           #3                  // String nanosecond timeout value out of range
      32: invokespecial #68                 // Method java/lang/IllegalArgumentException."<init>":(Ljava/lang/String;)V
      35: athrow
      36: iload_3
      37: ifle          44
      40: lload_1
      41: lconst_1
      42: ladd
      43: lstore_1
      44: aload_0
      45: lload_1
      46: invokevirtual #72                 // Method wait:(J)V
      49: return

  public final void wait() throws java.lang.InterruptedException;
    Code:
       0: aload_0
       1: lconst_0
       2: invokevirtual #72                 // Method wait:(J)V
       5: return

  protected void finalize() throws java.lang.Throwable;
    Code:
       0: return

  static {};
    Code:
       0: invokestatic  #71                 // Method registerNatives:()V
       3: return
}