4 threads were designed, of which two threads increased by 1 for J each time, while the other two threads reduced by 1 for J at a time. Write the program.

First, design a class to handle the addition and subtraction of this behavior:

 Public class manythread {    privateint j = 0;          Public synchronized void Inc () {        J++        ; + "Inc" + J);    }          Public synchronized void Dec () {        J--;         + "Dec" + j);}    }

And then make the call

 Public classMyTest {PrivateManythread Manythread =NewManythread ();  Public Static voidMain (string[] args) {MyTest MyTest=NewMyTest ();    Mytest.test (); }     Public voidTest () { for(inti = 0; I < 2;i++){            NewThread (NewRunnable () {@Override Public voidrun () { for(inti = 0;i < 20;i++) {manythread.inc ();            }}). Start (); NewThread (NewRunnable () {@Override Public voidrun () { for(inti = 0;i < 20;i++) {Manythread.dec ();        }}). Start (); }    }}

4 threads were designed, of which two threads increased by 1 for J each time, while the other two threads reduced by 1 for J at a time. Write the program.