How-to articles, tricks, and solutions about JAVA-8
:: (double colon) operator in Java 8
In Java 8, the :: (double colon) operator is used to refer to a method or a constructor.
Break or return from Java 8 stream forEach?
To break or return from a Java 8 Stream.forEach() operation, you can use the break or return statements as you would normally do in a loop.
Class has been compiled by a more recent version of the Java Environment
If you get the error "class has been compiled by a more recent version of the Java Environment", it means that you are trying to run a class file that was compiled with a newer version of Java than the one you have installed.
Convert java.time.LocalDate into java.util.Date type
To convert a java.time.LocalDate into a java.util.Date type in Java, you can use the atStartOfDay() method of the LocalDate class to get a LocalDateTime object and then use the toInstant() method to convert it to an Instant object.
Convert java.util.Date to java.time.LocalDate
To convert a java.util.Date object to a java.time.LocalDate object, you can use the java.time.Instant class to represent the date as an instant in time, and then use the java.time.LocalDateTime class to convert the instant to a date and time in the local
Error:java: javacTask: source release 8 requires target release 1.8
This error message usually indicates that you are trying to compile your Java code with a version of the javac compiler that is not compatible with the version of the Java language that your code is written in.
Find first element by predicate
To find the first element in a list that matches a certain condition, you can use the stream() method to create a stream from the list, and then use the filter() method to specify the condition that the element should satisfy. Finally, you can use the fin
Functional style of Java 8's Optional.ifPresent and if-not-Present?
The ifPresent() and ifPresentOrElse() methods of the Optional class in Java 8 provide a functional style way to perform different actions depending on whether the Optional object is empty or contains a value.
How can I parse/format dates with LocalDateTime? (Java 8)
In Java 8 and later, you can use the java.time.LocalDateTime class to represent a date and time without a time zone. To parse a date and time string into a LocalDateTime object, you can use the java.time.format.DateTimeFormatter class.