Core Java 面接の質問と回答

質問 111. If a variable is declared as private, where may the variable be accessed?

A private variable may only be accessed within the class in which it is declared.

質問 112. If a class is declared without any access modifiers, where may the class be accessed?

A class that is declared without any access modifiers is said to have package access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.

質問 113. What is a native method?

A native method is a method that is implemented in a language other than Java.

質問 114. What is reflection?

Reflection allows programmatic access to information about the fields, methods and constructors of loaded classes, and the use reflected fields, methods, and constructors to operate on their underlying counterparts on objects, within security restrictions.

質問 115. How can you achieve Multiple Inheritance in Java?

interface CanFight { 
	void fight(); 
}      

interface CanSwim { 
	void swim(); 
}      

interface CanFly { 
	void fly();
}
       
class ActionCharacter { 
	public void fight() {}
}       

class Hero extends ActionCharacter implements CanFight, CanSwim, CanFly { 
	public void swim() {}
	public void fly() {}
}

interface A { 
	void methodA();
} 

class AImpl implements A { 
	void methodA() { //do stuff }
}
 
interface B { 
	void methodB();
} 

class BImpl implements B { 
	void methodB() { //do stuff }
}
 
class Multiple implements A, B { 
	private A a = new A();
	private B b = new B();
	void methodA() { 
		a.methodA(); 
	}
	void methodB() { 
		b.methodB(); 
	}
}

class Multiple implements A, B { 
	private A a = new AImpl();
	private B b = new BImpl();
	void methodA() { 
		a.methodA(); 
	}
	void methodB() { 
		b.methodB(); 
	}
}