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Why Java needs Serializable interface?
...f this form makes the class internals part of the public API (which is why javadoc gives you the persisted forms of classes).
For long-term persistence, the class must be able to decode this form, which restricts the changes you can make to class design. This breaks encapsulation.
Serialization ca...
Which Java Collection should I use?
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@MattBall I agree with you for the most part. However Java LinkedList is a double linked list, so access at start and at end are both fast. You will note that of the branches above all three questions have to answer yes before I'd recommend using the LinkedList - so in other wor...
JPA or JDBC, how are they different?
I am learning Java EE and I downloaded the eclipse with glassfish for the same. I saw some examples and also read the Oracle docs to know all about Java EE 5. Connecting to a database was very simple. I opened a dynamic web project, created a session EJB , I used EntityManager and with the get meth...
Java int to String - Integer.toString(i) vs new Integer(i).toString()
Sometimes java puzzles me.
I have a huge amount of int initializations to make.
11 Answers
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String isNullOrEmpty in Java? [duplicate]
...d before, but Googling doesn't find it . Is there, in any of the standard java libraries (including apache/google/...), a static isNullOrEmpty() method for Strings ?
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Java: Get first item from a collection
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In java 8:
Optional<String> firstElement = collection.stream().findFirst();
For older versions of java, there is a getFirst method in Guava Iterables:
Iterables.getFirst(iterable, defaultValue)
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IntelliJ not recognizing a particular file correctly, instead its stuck as a text file
... note for googlers happening upon this, I had the exact same issue (with a Java file) with the same resolution; IntelliJ 13. When trying to create the file, I encountered the error 'Unable to parse template "Interface" Selected class file name mapped to not java'. Couldn't find that error message an...
How to sort an ArrayList?
I have a List of doubles in java and I want to sort ArrayList in descending order.
20 Answers
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How do I create a right click context menu in Java Swing?
...section on Bringing Up a Popup Menu in the How to Use Menus article of The Java Tutorials which explains how to use the JPopupMenu class.
The example code in the tutorial shows how to add MouseListeners to the components which should display a pop-up menu, and displays the menu accordingly.
(The ...
Static nested class in Java, why?
I was looking at the Java code for LinkedList and noticed that it made use of a static nested class, Entry .
14 Answers
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