Core Java Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

Core Java Interview Questions

Questions Answers Views Company eMail

printstream class method println() is calling using System class and its static object out .how it is explain any one in detail with example ?

TCS,

1 5308

whats the purposr of using serialization?

6 9435

how to one war file class to another war file class?

2029

suppose in a class there is a code like this: { Set hs=new Hashset(); hs.add(new Emp("kathy",1000)); hs.add(new Emp("kathy",2000)); } how can u avoid the above code in your class as set won't allow duplicate objects?

3 6495

what is meant by UP& DOWN casting in java?

6 14263

how can we import the user defined package without classpath?

CSC, Infosys,

1 7662

Write a java program to find the route that connects between Red and Green Cells. General Rules for traversal 1. You can traverse from one cell to another vertically, horizontally or diagonally. 2. You cannot traverse through Black cells. 3. There should be only one Red and Green cell and at least one of each should be present. Otherwise the array is invalid. 4. You cannot revisit a cell that you have already traversed. 5. The maze need not be in the same as given in the above example

2544

For ease of programming you can consider the maze as a 2D array with colors represented by below integer and characters (in capital letters). • B - Black • W -White • G- Green • R- Red R B W B W W W W W W B W B B W W W W W W W B W B W W W B W W W W B B W W W B W W W B W W B B B B W B W B W W B W W W B W W W B B B W W B W W W B W W B W B W W W B W B W W W W B B W W W W B W W W W W G Shortest Route Problem: • Solution that finds the shortest Route between Red and Green  White will have 1 Weight.  Red and Green carry no weights.  Shortest path is the path with less weight when you add up the weights in the path.

1983

what is j2se

3 6233

we have two threads..both the threads are reading the data.. is there any need of synchronization there?...justify it?

IBM,

4 8187

what is unreachable code problem in multiple catch statements

3 6451

where lives in jvm

5 8730

What is "Java Native Interface" and how to use it?

IBM,

1 5901

What is the diff. b/w Interfaces & Abstract class?

Ericsson,

6 10252

Which of these methods belong to Thread & Object class? join, yield, sleep, wait, notify

Ericsson,

3 9960

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Un-Answered Questions { Core Java }

What classes of exceptions may be caught by a catch clause in java programming?

1125

what invokes a threads run() method? : Java thread

969

What is jvm? How its run?

1030

What is public static?

987

What are classloaders?

976

What is the default size of set in java?

917

When is the finalize() called? What is the purpose of finalization?

1022

What are the different access modifiers available in java?

989

Explain what access modifiers can be used for variables?

1013

What is volatile data type?

955

Can substring create new object?

1067

Why java is said to be pass-by-value ?

991

Can you call one constructor from another if a class has multiple constructors?

981

What is pre increment and post increment in java?

951

What is the use of a copy constructor?

952

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