From 742574706bafdae32615bb3c85731a215035cfaf Mon Sep 17 00:00:00 2001 From: Mayuresh Kumbhar Date: Sun, 29 Sep 2024 04:29:02 +0200 Subject: [PATCH] [java/en] Update java.html.markdown with modern Java updates (#5128) --- java.html.markdown | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/java.html.markdown b/java.html.markdown index fc7383d8..24a9a47f 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -44,6 +44,9 @@ Multi-line comments look like this. import java.util.ArrayList; // Import all classes inside of java.security package import java.security.*; +// Java to illustrate calling of static members and methods without calling classname +import static java.lang.Math.*; +import static java.lang.System.*; public class LearnJava { @@ -211,9 +214,21 @@ public class LearnJava { // Prefer the String constructor when you need an exact value. BigDecimal tenCents = new BigDecimal("0.1"); + // Type inference with 'var' + var x = 100; // int + var y = 1.90; // double + var z = 'a'; // char + var p = "tanu"; // String + var q = false; // boolean + // Strings String fooString = "My String Is Here!"; + // Text blocks + vat textBlock = """ + This is a in Java + """; + // \n is an escaped character that starts a new line String barString = "Printing on a new line?\nNo Problem!"; // \t is an escaped character that adds a tab character @@ -459,6 +474,8 @@ public class LearnJava { System.out.println(br.readLine()); // In Java 7, the resource will always be closed, even if it throws // an Exception. + } catch (IOException | SQLException ex) { + // Java 7+ Multi catch block handle both exceptions } catch (Exception ex) { //The resource will be closed before the catch statement executes. System.out.println("readLine() failed."); @@ -852,6 +869,12 @@ public abstract class Mammal() } } +// Java Records are a concise way to define immutable data carrier classes, automatically +// generating boilerplate code like constructors, equals(), hashCode()and toString(). +// This automatically creates an immutable class Person with fields name and age. +public record Person(String name, int age) {} +Person p = new Person("Alice", 30); + // Enum Type // // An enum type is a special data type that enables for a variable to be a set