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

Core Java Interview Questions

Questions Answers Views Company eMail

Can we have a abstract class withought any method? What is a purspose of this?

3 6519

Howto get an object that will perform date & time calculations then format it for output in some different locales with different date style.can ne1 tel me the answer of this question.pls

1918

What is the difference between throw and throws?

Cap Gemini,

5 13249

I have an HashMap object, which has with key and value pair. It has 10 keys and values in that object. Now the question is I want insert new key and value in middle or any where in that list but not at the end or at the top. Is it possible or not. If yes how can we achieve this one?

Huawei,

2 7287

How can we handle runtime exceptions? write one sample program? Can we write runtime exceptions beside the throws key word? if yes write sample program?

Huawei,

1 7486

We are seeing so many videos/audios as many web sited. But question is these videos or audios are stored in Databases ( Oracle, Mysql, Sybase,... ) or stored any file directory from there they will give the link for that? Pls explain and give sample code to achieve this one? Thanks, Seenu.

Symphony,

1938

JSP is by default thread safe or not? what is the meaning of isThreadSafe="true" and isThreadSafe="false". Explain it? Thanks, Seenu

Huawei,

9 31504

Write program to print Hello World and print each character address in that string and print how many times each character is in that string? Ex: H: 0 & 1 e:1 & 1 l :2,3,8 & 3 o:4,6 & 2 w:5 & 1 r: 7 & 1 d 9 & 1

Huawei, IBM,

7 13248

how to know the total memory occupied by the objects in the ArrayList(Array list may contain duplicate objects)

Infosys, TCS,

2339

"We cannot create an object of interface but we can create a variable of it". Discuss the statement with the help of an example. (Plz help us to provide immediately.)

3 10952

Create a form of user Login in JSP, that accepts the user name and password from user and authenticate it with user names and passwords stored in database. (Plz provide me answer immediately)

ABC,

1 11793

what is diffrence between .NET and java?

2 5166

Read data from console and print in one file. That would be in C:\temp ? Thanks, Bose

Oracle, Surya Software,

3 8113

I have one POJO class(Java bean class), it has two variables for that it has setters and getters. Now i have created two objects for that class and i have set the data for those variables through this two objects. Now question is i want check whether those two objects have same data or not, for this write a program? Thanks, Bose.

Oracle,

2 16628

what is real-time example of runtime polymorphism and compile time polymorphism

SLK Group,

4 43509

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Un-Answered Questions { Core Java }

How to compare strings in java?

1012

What is array and arraylist in java?

1107

Why we use multi threading instead of multiprocessing?

1065

What is singleton service?

973

What is preparedstatement in java?

1047

List the interfaces which extends collection interface?

947

What is the difference between throw and throws keywords?

1052

What is %d in printf?

1040

What are the differences between Java 1.0 and Java 2.0?

2274

Is object a data type in java?

1115

How would overload a function based on return type?

969

When object is created and destroyed?

1103

List some important features of java 10 release?

1078

What is java english?

1002

Is 9 a prime number?

885

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