java examples

by 0 comments on "Sort an Array in Java"

public class Test { public static void main(String[] args) { int[] array = new int[]{7, 1, 9, 2, 5}; Arrays.sort(array); Arrays.stream(array).forEach(System.out::print); } } Output: 1 2 5 7 9   Note: values of type int will be automatically converted to the corresponding Wrapper class. And since the Integer Wrapper class implements Comparable, we can sort…

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by 0 comments on "Sort a List in Java"

import java.util.*; public class Test { public static void main(String[] args) { List<Integer> numbers = new ArrayList<>(Arrays.asList(7, 12, 5, 28, 97, 14, 2, 7, 8, 12, 19, 22)); Collections.sort(numbers); System.out.println(numbers); } } Output: [2, 5, 7, 7, 8, 12, 12, 14, 19, 22, 28, 97] Using the sort() method from ArrayList class public class Test…

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by 0 comments on "Iterate over a Map in Java"

class Test { public static void main(String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(1, “Java”); map.put(7, “Python”); map.put(10, “Ruby”); map.put(3, “Kotlin”); for (Map.Entry<Integer, String> entry : map.entrySet()) { System.out.println(“Key = ” + entry.getKey() + “, Value = ” + entry.getValue()); } } } Output: Key = 1, Value = Java Key = 3,…

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by 0 comments on "Check if the Number is Even or Odd in Java"

public class Test { public static void main(String[] args) { int num = 8; int num2 = 9; if(num % 2 == 0) { System.out.println(“num is an even number!”); } else { System.out.println(“num is odd number!”); } if(num2 % 2 == 0) { System.out.println(“num2 is an even number!”); } else { System.out.println(“num2 is odd number!”);…

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by 0 comments on "Check if String is Palindrome in Java"

public class Test { public static void main(String[] args) { String str = “racecar”; System.out.println(str.equals(new StringBuilder(str).reverse().toString())); } } Output: true   We can do the same with the StringBuffer class since it also has the reverse() method. Using the for loop public class Test { public static void main(String[] args) { String str = “racecar”;…

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by 0 comments on "Check if a String Contains a Substring in Java"

public class Test { public static void main(String[] args) { String str1 = “Learn Java Programming with alegrucoding.com”; String str2 = “Learn Java”; String str3 = “Simple Java Programming”; // check if str1 contains str2 if (str1.contains(str2)) { System.out.println(“str2 is present in str1”); } else { System.out.println(“str2 is not present in str1”); } // check…

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by 0 comments on "Generate a Random Number in Java"

public class Test { public static void main(String[] args) { // create an object of Random class Random random = new Random(); // Generate random integer 0 to 100 int randomInteger1 = random.nextInt(101); // Generate random integer 0 to 10000 int randomInteger2 = random.nextInt(10001); // Generate random double value double randomDouble = random.nextDouble(); // Generate…

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by 0 comments on "Find Max and Min Values of a List in Java"

public class Test { public static void main(String[] args) { List<Integer> list = new ArrayList<>(Arrays.asList(7, 19, 14, 1, 12, 22, 18, 3, 28, 5)); System.out.println(“Maximum value: ” + Collections.max(list)); System.out.println(“Minimum value: ” + Collections.min(list)); } } Output: Maximum value: 28 Minimum value: 1 Finding the maximum and minimum values in List using the Java 8…

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by 0 comments on "Get Substring from String in Java"

Output: Java   Methods from the StringUtils class that we can use to get a substring from String in Java: import org.apache.commons.lang3.StringUtils; public class Test { public static void main(String[] args) { String str = “Hello, my name is Tom, and I live in USA”; String substringBefore = StringUtils.substringBefore(str, “,”); String substringAfter = StringUtils.substringAfter(str, “,”); String substringBetween = StringUtils.substringBetween(str,…

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