public static java.lang.String conc(int);
    Code:
       0: ldc           #2                  // String a
       2: astore_1
       3: ldc           #2                  // String a
       5: astore_2
       6: iconst_0
       7: istore_3
       8: iload_3
       9: iload_0
      10: if_icmpge     39
      13: new           #3                  // class java/lang/StringBuilder
      16: dup
      17: invokespecial #4                  // Method java/lang/StringBuilder."<init>":()V
      20: aload_2
      21: invokevirtual #5                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      24: ldc           #2                  // String a
      26: invokevirtual #5                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      29: invokevirtual #6                  // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      32: astore_2
      33: iinc          3, 1
      36: goto          8
      39: aload_2
      40: areturn

  public static java.lang.String sb(int);
    Code:
       0: ldc           #2                  // String a
       2: astore_1
       3: new           #3                  // class java/lang/StringBuilder
       6: dup
       7: aload_1
       8: invokespecial #7                  // Method java/lang/StringBuilder."<init>":(Ljava/lang/String;)V
      11: astore_2
      12: iconst_0
      13: istore_3
      14: iload_3
      15: iload_0
      16: if_icmpge     32
      19: aload_2
      20: ldc           #2                  // String a
      22: invokevirtual #5                  // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
      25: pop
      26: iinc          3, 1
      29: goto          14
      32: aload_2
      33: invokevirtual #6                  // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
      36: areturn