Trending questions in Java

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Why “non-static method cannot be referenced from a static context”?

You can't call something that doesn't exist. ...READ MORE

Oct 17, 2018 in Java by sharth
• 3,370 points
1,697 views
0 votes
1 answer

varargs in Java

Well, varargs are generally used to deal ...READ MORE

Oct 31, 2018 in Java by code.reaper12
• 3,500 points
1,065 views
0 votes
1 answer

How to download a file from spring controllers?

@RequestMapping(value = "/files/{file_name}", method = RequestMethod.GET) public void ...READ MORE

Sep 4, 2018 in Java by code.reaper12
• 3,500 points
3,493 views
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1 answer

Java String interning

The String.intern() method of Java Strings ensures ...READ MORE

Oct 25, 2018 in Java by geek.erkami
• 2,680 points
1,244 views
0 votes
1 answer

Remote debugging a Java application

I noticed that some people are cutting ...READ MORE

Oct 16, 2018 in Java by Sushmita
• 6,920 points
1,640 views
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2 answers

How is hashmap different from hashtable?

HashMap and HashTable: 1) Hashtable and Hashmap implement ...READ MORE

Aug 1, 2018 in Java by samarth295
• 2,220 points
7,179 views
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1 answer

Plugin org.apache.maven.plugins:maven-resources-plugin:2.5 or one of its dependencies could not be resolved

Check the maven repository server is up. Check ...READ MORE

Jun 25, 2018 in Java by Sushmita
• 6,920 points
6,459 views
0 votes
1 answer

Error - trustAnchors parameter must be non-empty

This bizarre message means that the truststore ...READ MORE

Oct 29, 2018 in Java by Daisy
• 8,140 points
1,017 views
0 votes
1 answer

Constructor injection vs Setter injection in Spring Framework

Here, I have listed down few differences. ...READ MORE

Aug 30, 2018 in Java by anto.trigg4
• 3,440 points
3,630 views
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Optional return type of getter() in Java 8

Well, you can do that but originally ...READ MORE

Oct 23, 2018 in Java by code.reaper12
• 3,500 points
1,223 views
+1 vote
2 answers

Can I convert my Java program to an .exe file?

Launch4j is a cross-platform tool for wrapping ...READ MORE

Oct 18, 2018 in Java by Sushmita
• 6,920 points
4,263 views
0 votes
1 answer

Usage of abstract class and interface

Well let me draw a clear line ...READ MORE

Oct 23, 2018 in Java by geek.erkami
• 2,680 points
1,146 views
+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
3,485 views
0 votes
1 answer

notify() vs. notifyAll() in Java

notify() is used to wake any thread in the wait ...READ MORE

Sep 20, 2018 in Java by code.reaper12
• 3,500 points
2,507 views
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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
1,665 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
1,984 views
0 votes
1 answer

Static methods can't be abstract in Java

Well, Java doesn't allow this because of ...READ MORE

Oct 12, 2018 in Java by v.liyyah
• 1,300 points
1,499 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
6,059 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
1,471 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
1,326 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
1,951 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
866 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
3,759 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
1,441 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
832 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
1,053 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
1,302 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
1,822 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
4,456 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
941 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
1,104 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
3,764 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
6,315 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
6,733 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
4,927 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
2,169 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
5,254 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
2,292 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
1,260 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
1,048 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
3,863 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
6,096 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
2,200 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
1,508 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
2,359 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
5,924 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
2,515 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
5,271 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
5,310 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
6,108 views