public class SomeClass {
    private String a;
    private String b;
    private int c;

    public SomeClass() {
        c = 0;
    }

    public SomeClass(String a) {
        this();
        this.a = a;
    }

    public SomeClass(String a, String b) {
        this(a);
        this.b = b;
    }
}