code: public static String getConstantString(ConstantPool pool, int index) {
  
      Constant c = pool.getConstant(index);
      assert c != null : "Bad index " + index + " into pool";
      if (c instanceof ConstantUtf8) {
        return ((ConstantUtf8) c).getBytes();
      } else if (c instanceof ConstantClass) {
        ConstantClass cc = (ConstantClass) c;
        return cc.getBytes(pool) + " [" + cc.getNameIndex() + "]";
      } else {
        throw new Error("unexpected constant " + c + " of class " + c.getClass());
      }
    }
docs: Returns the constant string at the specified offset.
  
  @param pool the constant pool
  @param index the index in the constant pool
  @return the constant string at the specified offset in the constant pool