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 5472

whats the purposr of using serialization?

6 9937

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

2153

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 6770

what is meant by UP& DOWN casting in java?

6 14730

how can we import the user defined package without classpath?

CSC, Infosys,

1 7858

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

2640

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.

2062

what is j2se

3 6544

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

IBM,

4 8525

what is unreachable code problem in multiple catch statements

3 6713

where lives in jvm

5 9130

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

IBM,

1 6093

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

Ericsson,

6 10666

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

Ericsson,

3 10304

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Un-Answered Questions { Core Java }

What are identifiers in java?

1199

What are 3 data types?

1043

What is a nested structure?

1111

how to create multithreaded program? Explain different ways of using thread? : Java thread

1058

What is the difference between length and length () in java?

996

What is immutable class in java?

1004

What is type parameter in java?

1010

What is complexity in java?

1124

What does method mean?

1138

Differences between C and Java?

1296

What is nullpointerexception?

1125

What is printwriter in java?

1009

Tell me a few examples of final classes defined in Java API?

1167

What are internal variables?

1058

What are "methods" and "fields"?

1075

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