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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...
What is the Java string pool and how is “s” different from new String(“s”)? [duplicate]
...allows string constants to be reused, which is possible because strings in Java are immutable. If you repeat the same string constant all over the place in your Java code, you can actually have only one copy of that string in your system, which is one of the advantages of this mechanism.
When you u...
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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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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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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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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How to convert String to long in Java?
I got a simple question in Java: How can I convert a String that was obtained by Long.toString() to long ?
9 Answers
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Java time-based map/cache with expiring keys [closed]
Do any of you know of a Java Map or similar standard data store that automatically purges entries after a given timeout? This means aging, where the old expired entries “age-out” automatically.
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Why does flowing off the end of a non-void function without returning a value not produce a compiler
...ng so it doesn't force you to put a return at the bottom of the function.
javac, on the other hand, tries to verify that all code paths return a value and throws an error if it cannot prove that they all do. This error is mandated by the Java language specification. Note that sometimes it is wrong ...