code: private void pop( char c ) {
        if( this.top <= 0 || this.stack[this.top - 1] != c ){
           throw new JSONException( "Nesting error." );
        }
        this.top -= 1;
        this.mode = this.top == 0 ? 'd' : this.stack[this.top - 1];
     }
docs: Pop an array or object scope.
  
  @param c The scope to close.
  @throws JSONException If nesting is wrong.