public class T1 {
    volatile int n = 0;
    public void add() {
        n++;
    }
}

Compiled from "T1.java"
public class com.shishi.jmm.T1 {
  volatile int n;

  public com.shishi.jmm.T1();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: aload_0
       5: iconst_2
       6: putfield      #2                  // Field n:I
       9: return

  public void add();
    Code:
       0: aload_0
       1: dup
       2: getfield      #2                  // Field n:I
       5: iconst_1
       6: iadd
       7: putfield      #2                  // Field n:I
      10: return

  public static void main(java.lang.String[]);
    Code:
       0: return
}