Problems - Inheritance (till super keyword)

Level 1:

Basic single level inheritance

1)

Java Inheritance I | HackerRankHackerRank

2)

Java Inheritance II | HackerRankHackerRank

3)

Largest Tech Community | Hackathons, Programming & Coding Challenges | TechGig

Multilevel inheritance

1)

Largest Tech Community | Hackathons, Programming & Coding Challenges | TechGig

Basic method overriding

1)

Java Method Overriding | HackerRankHackerRank

2)

Java Method Overriding 2 (Super Keyword) | HackerRankHackerRank

3)

Largest Tech Community | Hackathons, Programming & Coding Challenges | TechGig

Level 2:

1) Resolve the compilation error :

package com.gs.ilp.corejava.Constructor;

public class ParentWithCon {
	String mem1;
	String mem2;

	public ParentWithCon(String mem1) {
		this.mem1 = mem1;
	}

	public ParentWithCon(String mem1, String mem2) {
		this.mem1 = mem1;
		this.mem2 = mem2;
	}

}

class ChildWithCon extends ParentWithCon {
	public ChildWithCon(String mem1) {
		super(mem1);
	}

	public ChildWithCon(String mem1, String mem2) {
		super(mem1, mem2);
	}
}

2) Whats the output ?

package com.gs.ilp.corejava.Constructor;

class AA {

	AA() {
		System.out.println("AA");
	}

	AA(int i) {
		this();
		System.out.println("AA " + i);
	}
}

class BB extends AA {
	BB() {
		System.out.println("BB");
	}

	BB(int i) {
		this();
		System.out.println("BB " + i);
	}
}

package com.gs.ilp.corejava.Constructor;

public class Problem2 {
	public static void main(String[] args) {
		new BB(4);
	}
}

Output :

AA
BB
BB 4

3) Whats the output ?

package com.gs.ilp.corejava.Constructor;

class AA {

	AA(int i) {
		this();
		System.out.println("AA " + i);
	}
}

class BB extends AA {
	BB() {
		System.out.println("BB");
	}

	BB(int i) {
		this();
		System.out.println("BB " + i);
	}
}

CTE

4) Will it compile ?

package com.gs.ilp.corejava.Constructor;

public class AAA {
	Object m1() {
		return null;
	}
}
class BBB extends AAA {
	String m1() {
		return null;
	}
}

5) Will it compile ?

package com.gs.ilp.corejava.Constructor;

public class AAA {

	void m1() {

	}
}

class BBB extends AAA {

	int m1() {
		return 0;
	}
}

6) Whats the output ?

package com.gs.ilp.corejava.Constructor;

class AAA {

	Object m1() {
		System.out.println("AAA m1");
		return null;
	}

}

class BBB extends AAA {

	String m1() {
		System.out.println("BBB m1");
		return null;
	}
}

public class Test2 {
	public static void main(String[] args) {
		AAA aaa = new AAA();
		aaa.m1();

		BBB bbb = new BBB();
		bbb.m1();

		AAA aba = new BBB();
		aba.m1();
	}
}

AAA m1
BBB m1
BBB m1

7) Will it compile ?

package com.gs.ilp.corejava.Constructor;

class Animal {

}

class Dog {

}

class Parent {
	Animal m1() {
		return null;
	}
}

class Child {
	Dog m1() {
		return null;
	}
}

public class Test3 {

}