public class HelloWorld {

    public static int x = 0;

    public static void main(String[] args) {

        HelloWorld.x = 45;

        System.out.println(HelloWorld.x);
    }
}

this.x = 42; //correct
this->x = 42; //will not compile as its not valid Java

public class Foo {

    private int x;

    public void setX(int x) {
        this.x = x;
    }

    public int getX() {
        return this.x;
    }
}

public class HelloWorld {

    public static void main(String[] args)
    {
        Foo foo = new Foo();
        foo.setX(45);

        System.out.println(foo.getX());
    }

}

public class HelloWorld {

    public int x = 0; // note: now it's an instance attribute

    public static void main(String[] args) {

        HelloWorld hw = new HelloWorld();


        System.out.println(hw.x);
    }

    public int getX() { return this.x; }
    public void setX(int x) { this.x = x; }
}

public class Foo {
    private int x;

    public void setX(int x) {
        this.x = x; //Here the keywork this is necessary!
    }

    public int getX() {
         return x; //in this case the 'x' can only be instance variable
    }
}

public class HelloWorld {
    public static void main(String[] args) {

        Foo foo1 = new Foo();
        Foo foo2 = new Foo(3, 4, 5);

        System.out.println("Foo1:n" + foo1);
        System.out.println("Foo2:n" + foo2);
    }
}

class Foo {
    private int x, y, z;

    public Foo() {
        this(-1, -1);
    }

    public Foo(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public Foo(int x, int y, int z) {
        this(x, y);
        this.z = z;
    }

    @Override
    public String toString() {
        return "x= " + x + "ny= " + y + "nz= " + z + "n";
    }
}

objectName.variableName = newValue

class Test {

int x;
int y;

public void Test(int x, int y) {
  this.x=x;
  this.y=y;
}

public void setX(int x) {
  this.x=x;
}
}