With netbeans 3.51 this source compiles fine. When executed 
it produce this error:
java.lang.NoSuchMethodError: cls_a.Geti2
at the line "System.out.println(oa.Geti2());"

When it run from the commandline it works all fine
------------------
class cls_a  {   
    public int i1; 
    private int i2;
    
    public int Geti2()  {  
        return(i2);  
    }
    public void Seti2(int i)  {   
        i2 = i;   
    }
}
public class ex001 {
    public static void main(String[] args) {
        System.out.println("Start main");     
        cls_a oa = new cls_a();     
        cls_a ob = new cls_a();      
        oa.i1 = 11;     
        ob.i1 = 101;   
        oa.Seti2(12);   
        ob.Seti2(22);     
        System.out.println(oa.i1);
        System.out.println(ob.i1);     
        System.out.println(oa.Geti2()); 
        System.out.println(ob.Geti2());	
        System.out.println(oa.toString());
        System.out.println(ob.toString());  
    }
    
}