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Create a File object in memory from a string in Java
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A File object in Java is a representation of a path to a directory or file, not the file itself. You don't need to have write access to the filesystem to create a File object, you only need it if you intend to actually write to the file (usi...
Is a Java hashmap search really O(1)?
I've seen some interesting claims on SO re Java hashmaps and their O(1) lookup time. Can someone explain why this is so? Unless these hashmaps are vastly different from any of the hashing algorithms I was bought up on, there must always exist a dataset that contains collisions.
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How to convert nanoseconds to seconds using the TimeUnit enum?
...g - convert() and the toFoo() methods all return longs now docs.oracle.com/javase/6/docs/api/java/util/concurrent/…
– Riking
Jul 30 '13 at 1:58
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Java Array Sort descending?
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Java 8:
Arrays.sort(list, comparator.reversed());
Update:
reversed() reverses the specified comparator. Usually, comparators order ascending, so this changes the order to descending.
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Catching java.lang.OutOfMemoryError?
Documentation for java.lang.Error says:
14 Answers
14
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What is the easiest/best/most correct way to iterate through the characters of a string in Java?
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@Matthias You can use the Javap class disassembler to see that the repeated calls to s.length() in for loop termination expression are indeed avoided. Note that in the code OP posted the call to s.length() is in the initialization expression, so the l...
Getting value of public static final field/property of a class in Java via reflection
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It's not an Android question, it's a Java reflection question that uses a particular example. Questions are tagged based on their topic.
– Matthew Read
Dec 19 '16 at 17:05
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When would you use the Builder Pattern? [closed]
...ow are some reasons arguing for the use of the pattern and example code in Java, but it is an implementation of the Builder Pattern covered by the Gang of Four in Design Patterns. The reasons you would use it in Java are also applicable to other programming languages as well.
As Joshua Bloch states...
How to check if my string is equal to null?
... I agree on the readability. It depends whether we are using Java 5 vs Java 6 since isEmpty() is only in Java 6.
– CoolBeans
Apr 8 '10 at 17:44
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Getting the IP address of the current machine using Java
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import java.net.DatagramSocket;
import java.net.InetAddress;
try(final DatagramSocket socket = new DatagramSocket()){
socket.connect(InetAddress.getByName("8.8.8.8"), 10002);
ip = socket.getLocalAddress().getHostAddress();
}
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