To invoke current class constructor

The this() constructor call can be used to invoke the current class constructor. It is used to reuse the constructor. In other words, it is used for constructor chaining. Following is the example for calling default constructor from parameterized constructor:

$\begin{lstlisting} class A{ A(){System.out.println(''hello a'');} A(int x){ ... ...public static void main(String args[]){ A a=new A(10); } } \end{lstlisting}$

Output:

$\begin{lstlisting} hello a 10 \end{lstlisting}$

Calling parameterized constructor from default constructor:

$\begin{lstlisting} class A{ A(){ this(5); System.out.println(''hello a''); }... ...s6{ public static void main(String args[]){ A a=new A(); }} \end{lstlisting}$

Output:
$\begin{lstlisting} 5 hello a \end{lstlisting}$