Frequent 'java' Questions - Stack Overflow

Score of 209

12 answers

4361517 views

What is a NullPointerException, and how do I fix it?

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from causing the program ...

Community wiki

Ziggy

Score of 723

23 answers

4849293 views

How do I compare strings in Java?

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it ...

Community wiki

Nathan H

Score of 7742

87 answers

2839558 views

Is Java "pass-by-reference" or "pass-by-value"?

I always thought Java uses pass-by-reference. However, I read a blog post which claims that Java uses pass-by-value. I don't think I understand the distinction the author is making. What is the ...

Community wiki

26 revs, 22 users 12%
user4315

Score of 364

25 answers

1074666 views

What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?

What does ArrayIndexOutOfBoundsException mean and how do I get rid of it? Here is a code sample that triggers the exception: String[] names = { "tom", "bob", "harry" }; for (int i = 0; i <= ...

Aaron

reputation score 11763

asked Apr 5, 2011 at 15:54

Score of 974

25 answers

913940 views

Scanner is skipping nextLine() after using next() or nextFoo()?

I am using the Scanner methods nextInt() and nextLine() for reading input. It looks like this: System.out.println("Enter numerical value"); int option; option = input.nextInt(); // Read ...

blekione

reputation score 10630

asked Oct 27, 2012 at 16:37

Score of 888

23 answers

565759 views

Unfortunately MyApp has stopped. How can I solve this?

I am developing an application, and everytime I run it, I get the message: Unfortunately, MyApp has stopped. What can I do to solve this? About this question - obviously inspired by What is a stack ...

nhaarman

reputation score 100719

asked Apr 28, 2014 at 23:55

Score of 2747

65 answers

1548593 views

How can I fix 'android.os.NetworkOnMainThreadException'?

I got an error while running my Android project for RssReader. Code: URL url = new URL(urlToRssFeed); SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser parser = factory....

bejoy george

reputation score 29905

asked Jun 14, 2011 at 12:02

Score of 823

15 answers

379616 views

What is a raw type and why shouldn't we use it?

Questions: What are raw types in Java, and why do I often hear that they shouldn't be used in new code? What is the alternative if we can't use raw types, and how is it better?

polygenelubricants

reputation score 385532

asked May 5, 2010 at 2:48

Score of 549

9 answers

152497 views

The Use of Multiple JFrames: Good or Bad Practice? [closed]

I'm developing an application which displays images, and plays sounds from a database. I'm trying to decide whether or not to use a separate JFrame to add images to the database from the GUI. I'm ...

Peddler

reputation score 6083

asked Mar 4, 2012 at 11:53

Score of 996

11 answers

150608 views

How do I write a correct micro-benchmark in Java?

How do you write (and run) a correct micro-benchmark in Java? I'm looking for some code samples and comments illustrating various things to think about. Example: Should the benchmark measure time/...

John Nilsson

reputation score 17385

asked Feb 2, 2009 at 17:39

Score of 555

19 answers

1745123 views

What does a "Cannot find symbol" or "Cannot resolve symbol" error mean?

Please explain the following about "Cannot find symbol", "Cannot resolve symbol" or "Symbol not found" errors (in Java): What do they mean? What things can cause them? ...

Stephen C

reputation score 724306

asked Sep 7, 2014 at 1:12

Score of 1357

38 answers

2603168 views

How to parse JSON in Java

I have the following JSON text. How can I parse it to get the values of pageName, pagePic, post_id, etc.? { "pageInfo": { "pageName": "abc", "pagePic":...

Muhammad Maqsoodur Rehman

reputation score 34327

asked Apr 7, 2010 at 9:00

Score of 248

11 answers

51603 views

How to add JTable in JPanel with null layout?

I want to add JTable into JPanel whose layout is null. JPanel contains other components. I have to add JTable at proper position.

Sagar

reputation score 2505

asked Apr 11, 2011 at 12:35

Score of 1773

31 answers

329948 views

How can I avoid Java code in JSP files, using JSP 2?

I know that something like the following three lines <%= x+1 %> <%= request.getParameter("name") %> <%! counter++; %> is an old school way of coding and in JSP version 2 ...

chmoelders

reputation score 18692

asked Jul 5, 2010 at 7:24

Score of 509

9 answers

71112 views

Should I avoid the use of set(Preferred|Maximum|Minimum) size methods in Java Swing?

Several times I've been criticized for having suggested the use of the following methods: setPreferredSize() setMinimumSize() setMaximumSize() on Swing components. I don't see any alternatives to ...

Heisenbug

reputation score 39290

asked Aug 29, 2011 at 11:02

Collectives™ on Stack Overflow

What is a NullPointerException, and how do I fix it?

How do I compare strings in Java?

Is Java "pass-by-reference" or "pass-by-value"?

What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?

Scanner is skipping nextLine() after using next() or nextFoo()?

Unfortunately MyApp has stopped. How can I solve this?

How can I fix 'android.os.NetworkOnMainThreadException'?

What is a raw type and why shouldn't we use it?

The Use of Multiple JFrames: Good or Bad Practice? [closed]

How do I write a correct micro-benchmark in Java?

What does a "Cannot find symbol" or "Cannot resolve symbol" error mean?

How to parse JSON in Java

How to add JTable in JPanel with null layout?

How can I avoid Java code in JSP files, using JSP 2?

Should I avoid the use of set(Preferred|Maximum|Minimum) size methods in Java Swing?

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