B.java

public class B {

        public Object lock = new Object();

        public String foo() {
                return "foo";
        }

        public synchronized String bar() {
                return "bar";
        }

        public String baz() {
                synchronized(this) {
                        return "baz";
                }
        }

        public String boo() {
                synchronized(lock) {
                        return "boo";
                }
        }

}

gistfile1.txt

// output of: javac B.java && javap -v B
Classfile /home/jeremy/src/jeremyheiler/asm/B.class
  Last modified Aug 11, 2014; size 628 bytes
  MD5 checksum 0b6c86d38f9f75eb4ba1d721c4c29874
  Compiled from "B.java"
public class B
  SourceFile: "B.java"
  minor version: 0
  major version: 51
  flags: ACC_PUBLIC, ACC_SUPER
Constant pool:
   #1 = Methodref          #2.#26         //  java/lang/Object."<init>":()V
   #2 = Class              #27            //  java/lang/Object
   #3 = Fieldref           #8.#28         //  B.lock:Ljava/lang/Object;
   #4 = String             #15            //  foo
   #5 = String             #17            //  bar
   #6 = String             #18            //  baz
   #7 = String             #23            //  boo
   #8 = Class              #29            //  B
   #9 = Utf8               lock
  #10 = Utf8               Ljava/lang/Object;
  #11 = Utf8               <init>
  #12 = Utf8               ()V
  #13 = Utf8               Code
  #14 = Utf8               LineNumberTable
  #15 = Utf8               foo
  #16 = Utf8               ()Ljava/lang/String;
  #17 = Utf8               bar
  #18 = Utf8               baz
  #19 = Utf8               StackMapTable
  #20 = Class              #29            //  B
  #21 = Class              #27            //  java/lang/Object
  #22 = Class              #30            //  java/lang/Throwable
  #23 = Utf8               boo
  #24 = Utf8               SourceFile
  #25 = Utf8               B.java
  #26 = NameAndType        #11:#12        //  "<init>":()V
  #27 = Utf8               java/lang/Object
  #28 = NameAndType        #9:#10         //  lock:Ljava/lang/Object;
  #29 = Utf8               B
  #30 = Utf8               java/lang/Throwable
{
  public java.lang.Object lock;
    flags: ACC_PUBLIC

  public B();
    flags: ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
         0: aload_0       
         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
         4: aload_0       
         5: new           #2                  // class java/lang/Object
         8: dup           
         9: invokespecial #1                  // Method java/lang/Object."<init>":()V
        12: putfield      #3                  // Field lock:Ljava/lang/Object;
        15: return        
      LineNumberTable:
        line 1: 0
        line 3: 4

  public java.lang.String foo();
    flags: ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: ldc           #4                  // String foo
         2: areturn       
      LineNumberTable:
        line 6: 0

  public synchronized java.lang.String bar();
    flags: ACC_PUBLIC, ACC_SYNCHRONIZED
    Code:
      stack=1, locals=1, args_size=1
         0: ldc           #5                  // String bar
         2: areturn       
      LineNumberTable:
        line 10: 0

  public java.lang.String baz();
    flags: ACC_PUBLIC
    Code:
      stack=2, locals=3, args_size=1
         0: aload_0       
         1: dup           
         2: astore_1      
         3: monitorenter  
         4: ldc           #6                  // String baz
         6: aload_1       
         7: monitorexit   
         8: areturn       
         9: astore_2      
        10: aload_1       
        11: monitorexit   
        12: aload_2       
        13: athrow        
      Exception table:
         from    to  target type
             4     8     9   any
             9    12     9   any
      LineNumberTable:
        line 14: 0
        line 15: 4
        line 16: 9
      StackMapTable: number_of_entries = 1
           frame_type = 255 /* full_frame */
          offset_delta = 9
          locals = [ class B, class java/lang/Object ]
          stack = [ class java/lang/Throwable ]


  public java.lang.String boo();
    flags: ACC_PUBLIC
    Code:
      stack=2, locals=3, args_size=1
         0: aload_0       
         1: getfield      #3                  // Field lock:Ljava/lang/Object;
         4: dup           
         5: astore_1      
         6: monitorenter  
         7: ldc           #7                  // String boo
         9: aload_1       
        10: monitorexit   
        11: areturn       
        12: astore_2      
        13: aload_1       
        14: monitorexit   
        15: aload_2       
        16: athrow        
      Exception table:
         from    to  target type
             7    11    12   any
            12    15    12   any
      LineNumberTable:
        line 20: 0
        line 21: 7
        line 22: 12
      StackMapTable: number_of_entries = 1
           frame_type = 255 /* full_frame */
          offset_delta = 12
          locals = [ class B, class java/lang/Object ]
          stack = [ class java/lang/Throwable ]

}