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Add leading zeroes to number in Java? [duplicate]
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String.format (https://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html#syntax)
In your case it will be:
String formatted = String.format("%03d", num);
0 - to pad with zeros
3 - to set width to 3
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How to get an enum value from a string value in Java?
...reated at compile time and do not appear in source code. They do appear in Javadoc, though; for example, Dialog.ModalityType shows both methods.
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warning: [options] bootstrap class path not set in conjunction with -source 1.5
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From a blog post:
To use javac from JDK N to cross-compiler to an older platform version, the correct practice is to:
Use the older -source setting.
Set the bootclasspath to compile against the rt.jar (or equivalent) for the older platform....
“Insert if not exists” statement in SQLite
...OR REPLACE INTO table () values();
For more information, see: sqlite.org/lang_insert
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How can I check if multiplying two numbers in Java will cause an overflow?
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Java 8 has Math.multiplyExact, Math.addExact etc. for ints and long. These throw an unchecked ArithmeticException on overflow.
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Can I set enum start value in Java?
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Java enums are not like C or C++ enums, which are really just labels for integers.
Java enums are implemented more like classes - and they can even have multiple attributes.
public enum Ids {
OPEN(100), CLOSE(200);
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Converting List to List
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Solution for Java 8. A bit longer than the Guava one, but at least you don't have to install a library.
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
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List<Integer> integers = Arrays.asL...
Java Garbage Collection Log messages
I have configured java to dump garbage collection information into the logs ( verbose GC ). I am unsure of what the garbage collection entries in the logs mean. A sample of these entries are posted below. I've searched around on Google and have not found solid explanations.
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What is Double Brace initialization in Java?
What is Double Brace initialization syntax ( {{ ... }} ) in Java?
13 Answers
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No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
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On your Eclipse IDE, go into Window > Preferences > Java > Installed JREs > and check your installed JREs. You should have an entry with a JDK there.
Select the Execution Env as show below. Click OK
Then Right-Click on your Project -> Maven -> Update Project
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