Setting the default Java character encoding - Stack Overflow
By setting the (Windows) environment variable JAVA_TOOL_OPTIONS to -Dfile.encoding=UTF8, the (Java) System property will be set automatically every time a JVM is started. You will know that the parameter has been picked up because the following message will be posted to System.err: Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
java - Getting the difference between two sets - Stack Overflow
Java 8. We can make use of removeIf which takes a predicate to write a utility method as: // computes the difference without modifying the sets public static <T> Set<T> differenceJava8(final Set<T> setOne, final Set<T> setTwo) { Set<T> result = new HashSet<T>(setOne); result.removeIf(setTwo::contains); return result; }
sorting - Java Set retain order? - Stack Overflow
2012年5月25日 · @White_King: A set is a mathematical concept that does not contain the notion of "insertion order" so it makes sense for the Java interface to follow its conventions. There are ordered sets but the order is specified by a relation (comparator in Java), again matching the definition in set theory with the definition in Java.
Duplicate elements in java.util.Set - Stack Overflow
2021年12月30日 · When the hash changes between the first and second add a different bucket is used in the java.util.HashMap and the object is in the set twice. The code sample may look a little contrieved but I've seen this happen in the wild with domain classes where the hash is created from mutable fields and the equals method hasn't been kept in sync with ...
How do I iterate and modify Java Sets? - Stack Overflow
You can safely remove from a set during iteration with an Iterator object; attempting to modify a set through its API while iterating will break the iterator. the Set class provides an iterator through getIterator().
java - How do I set the proxy to be used by the JVM - Stack Overflow
2008年9月23日 · Set the JVM flags http.proxyHost and http.proxyPort when starting your JVM on the command line. This is usually done in a shell script (in Unix) or bat file (in Windows). Here's the example with the Unix shell script: JAVA_FLAGS=-Dhttp.proxyHost=10.0.0.100 -Dhttp.proxyPort=8800 java ${JAVA_FLAGS} ...
wait - How do I make a delay in Java? - Stack Overflow
If you want to pause then use java.util.concurrent.TimeUnit: TimeUnit.SECONDS.sleep(1); To sleep for one second or. TimeUnit.MINUTES.sleep(1); To sleep for a minute. As this is a loop, this presents an inherent problem - drift. Every time you run code and then sleep you will be drifting a little bit from running, say, every second.
Increase heap size in Java - Stack Overflow
2016年3月22日 · This only works with 64 bit version of Java. Go to Control Panel and click on the Java icon. On the small window of Java Control Panel, click on the Java menu bar and then click on view button. If you have two Java platforms, disable the previous version of Java, then click on Runtime parameters text field and write -Xmx1024m or less than RAM ...
java - What is a classpath and how do I set it? - Stack Overflow
2010年3月7日 · Simply put, the classpath is just a set of paths where the java compiler and the JVM must find needed classes to compile or execute other classes. Let's start with an example, suppose we have a Main.java file thats under C:\Users\HP\Desktop\org\example ,
Creating subset of a Set in Java - Stack Overflow
2018年1月22日 · I have a LinkedHashSet, i.e an ordered set. I'm trying to find a function to just return a subset of the set, i.e the first 20 elements of the set. I know I can do it by creating a new set and then populating using an iteration of the first set but I …