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What is the difference between ? and Object in Java generics?
I'm using Eclipse to help me clean up some code to use Java generics properly. Most of the time it's doing an excellent job of inferring types, but there are some cases where the inferred type has to be as generic as possible: Object. But Eclipse seems to be giving me an option to choose between a...
What is the default access specifier in Java?
I just started reading a Java book and wondered; which access specifier is the default one, if none is specified?
12 Answer...
is there a Java equivalent to null coalescing operator (??) in C#? [duplicate]
Is it possible to do something similar to the following code in Java
6 Answers
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Override valueof() and toString() in Java enum
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Until Enums are fixed in Java, @Bat has a more appropriate and OO friendly solution. name() should not be final.
– Andrew T Finnell
Aug 15 '18 at 14:53
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Efficiency of Java “Double Brace Initialization”?
In Hidden Features of Java the top answer mentions Double Brace Initialization , with a very enticing syntax:
15 Answe...
How to convert a Java 8 Stream to an Array?
What is the easiest/shortest way to convert a Java 8 Stream into an array?
10 Answers
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Comparing boxed Long values 127 and 128
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TL;DR
Java caches boxed Integer instances from -128 to 127. Since you are using == to compare objects references instead of values, only cached objects will match. Either work with long unboxed primitive values or use .equals() to ...
Get a list of all threads currently running in Java
... I haven't timed these specific alternatives, but I've worked with other Java means of gathering stack traces vs just a list of threads. The performance impact seems to depend very strongly on which JVM you are using (JRockit vs Sun JVM for example). It's worth measuring in your specific instanc...
invalid target release: 1.7
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You need to set JAVA_HOME to your jdk7 home directory, for example on Microsoft Windows:
"C:\Program Files\Java\jdk1.7.0_40"
or on OS X:
/Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk/Contents/Home
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How to directly initialize a HashMap (in a literal way)?
Is there some way of initializing a Java HashMap like this?:
14 Answers
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