Java Questions

Non-static member class is a class defined inside outer class with out static modifier.

EX:

class A { // top level class or outer class

    ......

    class B { //non-static member class

    }

    .....

}

boolean isFile();

For inserting, deleting, and locating elements in a Map, the HashMap offers the best alternative. If, however, you need to traverse the keys in a sorted order, then TreeMap is your better alternative. Depending upon the size of your collection, it may be faster to add elements to a HashMap, then convert the map to a TreeMap for sorted key traversal.

A thread can be created by subclassing Thread, or by implementing the Runnable interface.

long lastModified();

we can give this return value to a date object and we can get data to be displayed.

When an exception is thrown , the catch block of the try statement are examined in the order in which they appear. The first catch block that is capable of handling the exception is executed. The remaining catch blocks are ignored

Overriding means changing behavior of methods of base class in derive class by overriding the base class methods. If class A is a base class with method ’calculate’ and class B inherits class A, thus derives method ’calculate’ of class A. The behavior of ’calculate’ in class B can be changed by overriding it.

These are accessibility modifiers. Private is the most restrictive, while public is the least restrictive. There is no real difference between protected and the default type (also known as package protected) within the context of the same package, however the protected keyword allows visibility to a derived class in a different package.