Java Archives - Page 316 of 336

How to extract .war files in java? ZIP vs JAR

If you look at the JarFile API you’ll see that it’s a subclass of the ZipFile class. The jar-specific classes mostly just add jar-specific functionality, like direct ...

April 2, 2022
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Is there a way to simulate the C++ ‘friend’ concept in Java?

The ‘friend’ concept is useful in Java, for example, to separate an API from its implementation. It is common for implementation classes to ...

April 2, 2022
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Can an int be null in Java?

int can’t be null, but Integer can. You need to be careful when unboxing null Integers since this can cause a lot of confusion and head scratching! ...

April 2, 2022
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What’s the difference between HashSet and Set?

A Set represents a generic “set of values”. A TreeSet is a set where the elements are sorted (and thus ordered), a HashSet is a set where the elements ...

April 2, 2022
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Unable to resolve host “” No address associated with host name

You probably don’t have the INTERNET permission. Try adding this to your AndroidManifest.xml file, right before </manifest>: <uses-permission android:name="android.permission.INTERNET" /> Note: the above doesn’t have to be right before the </manifest> tag, ...

April 2, 2022
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Is there a way to end the program if statement is false?

April 2, 2022
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Netbeans – Error: Could not find or load main class

Right click on your Project in the project explorer Click on properties Click on Run Make sure your Main Class is the one ...

April 2, 2022
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Exception in thread “main” java.net.BindException: Address already in use – Error in Netbeans only

The way to achieve what I want is to right-click on the particular class (ex. Server.java) that I want to run and select “Run ...

April 2, 2022
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Java Fraction Calculator

When you class mates tell you, that you didn’t call the reduce method, they mean, that you never use the reduce method. Your add-method should look somewhat ...

April 2, 2022
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How to convert a date to milliseconds

You don’t have a Date, you have a String representation of a date. You should convert the String into a Date and then obtain the milliseconds. To convert a String into a Date and ...

April 2, 2022
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