void waitForSignal() {

Object obj = new Object();

synchronized (Thread.currentThread()) {

obj.wait();

obj.notify();

}

}

Which statement is true?

The Void class has one field, TYPE, which holds a reference to the Class object for the type void.

deleteCharAt() method deletes the character at the specified index location and returns the resulting StringBuffer object.

So after deleting the character at 0 ie 'H', the string returns 'ello' as the output.

A poor Hashcode() function will result in frequent collision in HashMap which eventually increase time for adding an object into Hash Map.

Stored procedure should return error code if some operation fails but if stored procedure itself fail than catching SQLException is only choice.

When we create string with new() Operator, it’s created in heap and not added into string pool while String created using literal are created in String pool itself which exists in PermGen area of heap.

String s = new String("Test");

does not put the object in String pool , we need to call String.intern() method which is used to put them into String pool explicitly. its only when you create String object as String literal e.g. String s = "Test" Java automatically put that into String pool.

Immutable classes are Java classes whose objects can not be modified once created. Any modification in Immutable object result in new object. For example is String is immutable in Java. Mostly Immutable are also final in Java, in order to prevent sub class from overriding methods in Java which can compromise Immutability. You can achieve same functionality by making member as non final but private and not modifying them except in constructor.

In order to use any object as Key in HashMap, it must implements equals and hashcode method in Java.