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Showing posts with the label Java 8

Java Program To Convert String To HashMap

Example 1: Convert  below String String str = "[name = rahul:email = rahul@knf.co.in:gender = male]" ; to HashMap Solution 1:   public static void main( String [] args) { String str = "[name = rahul:email = rahul@knf.co.in:gender = male]" ; //Remove square brackets str = str.substring( 1 , str.length() - 1 ); //Split the string by : to get key-value pairs String [] keyValuePairs = str.split( ":" ); Map < String , String > map = new HashMap <>(); //Iterate over the pairs for ( String pair : keyValuePairs) { //Split the pairs to get key and value String [] entry = pair.split( "=" ); //Add them to the hashmap and trim whitespaces map.put(entry[ 0 ].trim(), entry[ 1 ].trim()); } System.out.println(map); } Solution 2: Using Java 8 Stream public static void main( String [] a

Learn Java Predicate, Consumer, Function, and Supplier (Functional Interfaces) with Example

Java is Object Oriented Programming language, being object-oriented is not bad, but it brings a lot of verbosity to the program.Java 8 introduced new libraries and programming styles, for example, functional interfaces, lambda expressions, and streams. These bring functional-style programming to the object-oriented programming capabilities of Java. Java Functional Interface and Lambda Expression help us write smaller and cleaner code by removing much boilerplate code.  A functional interface contains only a single abstract method and  can include default and static methods that do have an implementation and a single unimplemented method. Here we will discuss Predicate, Consumer, Function, and Supplier. 1. Predicate Interface The Predicate is a functional interface defined in java. util. Function package , which accepts an argument and returns a boolean. This is mainly used to filter data from a Java Stream. The filter method of a stream accepts a predicate to filter the data and retur