Trending questions in Java

+1 vote
1 answer

How to calculate days between two dates?

You are making some conversions with your ...READ MORE

Aug 28, 2018 in Java by Frankie
 • 9,830 points • 2,930 views
0 votes
1 answer

Number of Characters in Java String

I think you can make use of ...READ MORE

Oct 23, 2018 in Java by anto.trigg4
 • 3,440 points • 521 views
0 votes
1 answer

Recursively delete directories in Java

You can try using the FileUtils class of Apache's commons-io: FileUtils.deleteDirectory(new ...READ MORE

Oct 23, 2018 in Java by code.reaper12
 • 3,500 points • 513 views
0 votes
1 answer

Tail call optimization in JVM

The tail call optimization in JVM is difficult ...READ MORE

Oct 10, 2018 in Java by geek.erkami
 • 2,680 points • 1,050 views
+2 votes
1 answer

What is the meaning of "this" keyword in Java?

public class MyThisTest { private int ...READ MORE

Oct 10, 2018 in Java by Daisy
 • 8,140 points • 928 views
0 votes
1 answer

System.exit() method in Java

System.exit() is a method of System class ...READ MORE

Sep 28, 2018 in Java by code.reaper12
 • 3,500 points • 1,541 views
0 votes
1 answer

What is the meaning of 'Synchronized'?

The synchronized keyword is about different threads reading and ...READ MORE

Oct 17, 2018 in Java by Parth
 • 4,640 points • 689 views
0 votes
2 answers

C++ performance vs. Java/C#

The overhead of interpreting code is much higher than ...READ MORE

Dec 27, 2018 in Java by iangregor
 • 300 points • 1,351 views
0 votes
1 answer

Java equals() vs Arrays.equals()

Here, array1.equals(array2)meansarray1 == array2 That is, it checks whether ...READ MORE

Oct 11, 2018 in Java by code.reaper12
 • 3,500 points • 911 views
0 votes
1 answer

How to use ThreadLocal variable

You can use a ThreadLocal variable when you have some ...READ MORE

Oct 11, 2018 in Java by code.reaper12
 • 3,500 points • 895 views
0 votes
1 answer

How can we add local .jar file dependency to build.gradle file?

You can refer the below code if ...READ MORE

Jun 27, 2018 in Java by Akrati
 • 960 points • 5,406 views
0 votes
1 answer

Java's default package

Yes, technically, using the package names should ...READ MORE

Oct 9, 2018 in Java by code.reaper12
 • 3,500 points • 936 views
0 votes
1 answer

Randomly selecting an element from an array

For randomly selecting an element, java.util.Random provides ...READ MORE

Oct 11, 2018 in Java by anto.trigg4
 • 3,440 points • 760 views
0 votes
1 answer

Importing properties file from Java package

In case your class is present within ...READ MORE

Oct 15, 2018 in Java by code.reaper12
 • 3,500 points • 567 views
0 votes
1 answer

Non-static method within Static method in Java

As per my knowledge, you are getting this error ...READ MORE

Sep 28, 2018 in Java by anto.trigg4
 • 3,440 points • 1,279 views
0 votes
1 answer

How to display an animated GIF?

Android actually can decode and display animated ...READ MORE

Oct 8, 2018 in Java by sharth
 • 3,370 points • 755 views
0 votes
1 answer

System.currentTimeMillis vs System.nanoTime

In case you want extremely precise measurements ...READ MORE

Aug 10, 2018 in Java by code.reaper12
 • 3,500 points • 3,244 views
0 votes
1 answer

How do you produce a double in Java

double num = 5; When you do this, ...READ MORE

Oct 4, 2018 in Java by anto.trigg4
 • 3,440 points • 893 views
0 votes
2 answers

How can I Copy files from one directory to another in Java

Java 8 Path sourcepath = Paths.get("C:\\data\\temp\\mydir"); ...READ MORE

Aug 10, 2018 in Java by samarth295
 • 2,220 points • 4,454 views
+1 vote
1 answer

Performance difference of if/else vs switch statement in Java

The thing you are worried about is ...READ MORE

Jul 26, 2018 in Java by geek.erkami
 • 2,680 points • 3,778 views
0 votes
1 answer

@Qualifier annotation in Spring Framework

When you create more than one bean ...READ MORE

Sep 10, 2018 in Java by code.reaper12
 • 3,500 points • 1,822 views
0 votes
1 answer

Join array elements with a separator in Java

Using Java 8, you can easily perform ...READ MORE

Aug 16, 2018 in Java by geek.erkami
 • 2,680 points • 2,879 views
+1 vote
1 answer

What if several ports required by tomacat server at local host are already in use

You've another instance of Tomcat already running. ...READ MORE

May 31, 2018 in Java by Akrati
 • 3,190 points • 6,165 views
0 votes
2 answers

How can we assert, that a certain Exception is thrown in JUnit 4 tests?

@Test(expected = IndexOutOfBoundsException.class) public void testIndexOutOfBoundsException() { ...READ MORE

Dec 10, 2018 in Java by Sushmita
 • 6,920 points • 1,606 views
0 votes
1 answer

Fixing android.os.NetworkOnMainThreadException in Java

Android has some good tips on good ...READ MORE

Jun 12, 2018 in Java by Rishabh
 • 3,620 points • 5,585 views
0 votes
2 answers

“Could not find or load main class” mean?

Use the final modifier to enforce good initialization. Avoid returning ...READ MORE

Sep 18, 2018 in Java by Sushmita
 • 6,920 points • 4,563 views
0 votes
2 answers

How to left pad a string with zero in java?

String paddedString = org.apache.commons.lang.StringUtils.leftPad("129018", 10, "0") the second ...READ MORE

Aug 31, 2018 in Java by Sushmita
 • 6,920 points • 3,228 views
0 votes
1 answer

How can we get the current location in Android?

First you need to define a LocationListener to handle ...READ MORE

Sep 25, 2018 in Java by Parth
 • 4,640 points • 944 views
0 votes
1 answer

Java anonymous code blocks

The anonymous code blocks in Java are ...READ MORE

Sep 5, 2018 in Java by anto.trigg4
 • 3,440 points • 1,778 views
0 votes
1 answer

How to pass an object from one activity to another on Android

One option could be letting your custom ...READ MORE

Jun 25, 2018 in Java by Rishabh
 • 3,620 points • 4,874 views
0 votes
1 answer

How to prevent java.lang.NumberFormatException in Java?

"N/A" is not integer. It must throw NumberFormatException if you ...READ MORE

Jun 26, 2018 in Java by sharth
 • 3,370 points • 4,802 views
0 votes
2 answers

Determining Class of an Object in Java

You can use: Object instance = new SomeClass(); instance.getClass().getName(); ...READ MORE

Nov 26, 2018 in Java by Sushmita
 • 6,920 points • 1,996 views
+12 votes
3 answers

How do I set or change the PATH system variable?

First make sure you have installed JDK ...READ MORE

Aug 28, 2018 in Java by slayer
 • 29,370 points • 1,481 views
0 votes
1 answer

What is the best Java email address validation method?

Apache Commons is generally known as a ...READ MORE

Sep 26, 2018 in Java by Parth
 • 4,640 points • 785 views
0 votes
1 answer

Various Advice in Spring AOP

Below are the various advices available in AOP: Before: These types ...READ MORE

Sep 12, 2018 in Java by geek.erkami
 • 2,680 points • 1,395 views
0 votes
1 answer

How to call a method after a delay in Android using Java?

final Handler handler = new Handler(); handler.postDelayed(new Runnable() ...READ MORE

Jun 11, 2018 in Java by Akrati
 • 3,190 points • 5,366 views
0 votes
1 answer

Use Servlets with Ajax

Here, we are going to create the ...READ MORE

Jul 16, 2018 in Java by Akrati
 • 3,190 points • 3,848 views
0 votes
1 answer

Spring AOP vs AspectJ AOP

Well, below I have listed down few ...READ MORE

Sep 10, 2018 in Java by v.liyyah
 • 1,300 points • 1,389 views
0 votes
3 answers

How to read input from Console using Scanner Class?

A simple example: import java.util.Scanner; public class Expl { ...READ MORE

Aug 1, 2018 in Java by samarth295
 • 2,220 points • 5,280 views
0 votes
1 answer

What is the simplest way to read JSON from a URL in java

Read json from url use url.openStream() and read contents ...READ MORE

Jun 13, 2018 in Java by samarth295
 • 2,220 points • 5,208 views
0 votes
1 answer

Simple HTTP server in Java using only Java SE API

You can write a pretty simple embedded Jetty Java ...READ MORE

Aug 29, 2018 in Java by Parth
 • 4,640 points • 1,884 views
0 votes
1 answer

Good Hash Function for Strings

Usually hashes wouldn't do sums, otherwise, stop and pots will have ...READ MORE

Jul 19, 2018 in Java by Akrati
 • 960 points • 3,628 views
0 votes
1 answer

Increasing the JVM memory using command line

You can adjust your JVM memory needs by ...READ MORE

Sep 25, 2018 in Java by geek.erkami
 • 2,680 points • 673 views
0 votes
1 answer

What is the difference between hashset and treeset?

HashSet vs TreeSet: 1- Hashset gives better performance (faster) ...READ MORE

Jun 20, 2018 in Java by Akrati
 • 3,190 points • 4,812 views
0 votes
2 answers

Ho do I Iterate through a HashMap which contains duplicate values

for (Map.Entry<String, String> item : params.entrySet()) { ...READ MORE

Jul 24, 2018 in Java by samarth295
 • 2,220 points • 5,336 views
0 votes
1 answer

Unescaping HTML character entities in Java

I guess you can use this function: StringEscapeUtils.unescapeH ...READ MORE

Sep 25, 2018 in Java by anto.trigg4
 • 3,440 points • 546 views
0 votes
1 answer

Why is the Scanner skipping nextLine() after using next() or nextFoo()

public static void main(String[] args) { ...READ MORE

Aug 28, 2018 in Java by samarth295
 • 2,220 points • 1,750 views
0 votes
1 answer

Can we convert a string to hexadecimal in java

I find this to be an easy ...READ MORE

Jul 4, 2018 in Java by Akrati
 • 3,190 points • 4,073 views
0 votes
2 answers

Java Environment Variables

--- To set java path --- There are ...READ MORE

Dec 3, 2018 in Java by Sushmita
 • 6,920 points • 1,475 views
0 votes
2 answers

How can I do url string decoding in java

We can use URLDecoder: URLDecoder.decode( url, "UTF-8" ); READ MORE

Dec 7, 2018 in Java by Sushmita
 • 6,920 points • 838 views
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