Println

               System.out.println(1+2+"sd");//3sd
               System.out.println("_"+12+3); //_123
               System.out.println("_"+(1+2+3)); //_6

Test print

    //System.out.println(...)
    @Test
    public void testPrinta(){

        float x=10/3; //x=3.0
        float y= (float)10/3; //y=3.3333333
        float z= 10/(float)3; //y=3.3333333

        prn(1+2+2+"ok"); //5ok
        prn("ok" + new String("nie")); //oknie
        prn("OK"+(3-1));//ok2
        //!prn("ok"+9-6);   //nie da się
    }

Test println zmiennych

public class Main {
           //typ     nazwa     wart domyślna
    static boolean _boolean;   //boolean
    static char    _char;      //'\u0000'
    static byte    _byte;      //(byte)0
    static short   _short;     //(short)0
    static int     _int;       //0
    static long    _long;      //0L
    static float   _float;     //0.0f
    static double  _double;    //0.0d

    public static void main(String[] args) {
        System.out.println(_boolean); //false
        System.out.println(_char);    //jakiś kwadracik
        System.out.println(_byte);    //0
        System.out.println(_short);   //0
        System.out.println(_int);     //0
        System.out.println(_long);    //0
        System.out.println(_float);   //0.0
        System.out.println(_double);  //0.0
    }
}