Java8 Programming Examples

Java Program to evaluate mathematical expressions in String

java8

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
public class Main {
	public static void main(String[] args) throws Exception {
		ScriptEngineManager scriptEngineManager  = new ScriptEngineManager();
		ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("JavaScript");
		// JavaScript code from String
		Object ob = scriptEngine.eval("9 + 15 + 30");
		System.out.println("Result of evaluating mathematical expressions in String = "+ob);
	}
}

Java equals() method

java8

public class Sample {
   public static void main(String []args) {
      String s1 = "tutorialspoint";
      String s2 = "tutorialspoint";
      String s3 = new String ("Tutorials Point");
      System.out.println(s1.equals(s2));
      System.out.println(s2.equals(s3));
   }
}

Java Program to Compare Two Strings

java8

import java.lang.*;
public class StringDemo {
   public static void main(String[] args) {
      String str1 = "tutorials", str2 = "point";
      // comparing str1 and str2
      int retval = str1.compareTo(str2);
      // prints the return value of the comparison
      if (retval < 0) {
         System.out.println("str1 is greater than str2");
      }
      else if (retval == 0) {
         System.out.println("str1 is equal to str2");
      }
      else {
         System.out.println("str1 is less than str2");
      }
   }
}

Java String equals() method

java8

public class Sample{
   public static void main(String []args){
      String s1 = "tutorialspoint";
      String s2 = "tutorialspoint";
      String s3 = new String ("Tutorials Point");
      System.out.println(s1.equals(s2));
      System.out.println(s2.equals(s3));
   }
}

String compare by equals() method in Java

java8

public class Test {
   public static void main(String args[]) {
      Integer x = 5;
      Integer y = 10;
      Integer z =5;
      Short a = 5;
      System.out.println(x.equals(y));
      System.out.println(x.equals(z));
      System.out.println(x.equals(a));
   }
}

Append method in Java

java8

import java.lang.*;
public class StringBufferDemo {
   public static void main(String[] args) {
      StringBuffer buff = new StringBuffer("tuts ");
      System.out.println("buffer = " + buff);
     
      // appends the char argument as string to the string buffer.
      buff.append('A');
     
      // print the string buffer after appending
      System.out.println("After append = " + buff);
      buff = new StringBuffer("abcd ");
      System.out.println("buffer = " + buff);
     
      // appends the char argument as string to the string buffer.
      buff.append('!');
     
      // print the string buffer after appending
      System.out.println("After append = " + buff);
   }
}

Java string comparison sample code

java8

import java.lang.*;
public class StringDemo {
   public static void main(String[] args) {
      String str1 = "tutorials", str2 = "point";
      // comparing str1 and str2
      int retval = str1.compareTo(str2);
      System.out.println(str1==str2);
      
      // prints the return value of the comparison
      if (retval < 0) {
      System.out.println("str1 is greater than str2");
      } else if (retval == 0) {
         System.out.println("str1 is equal to str2");
      } else {
         System.out.println("str1 is less than str2");
      }
   }
}

String in Switch Case in Java

java8

public class Test {
   public static void main(String args[]) {
      // char grade = args[0].charAt(0);
      char grade = 'C';
      switch(grade) {
         case 'A' :
            System.out.println("Excellent!");
            break;
         case 'B' :
         case 'C' :
            System.out.println("Well done");
            break;
         case 'D' :
            System.out.println("You passed");
         case 'F' :
            System.out.println("Better try again");
            break;
         default :
            System.out.println("Invalid grade");
      }
      System.out.println("Your grade is " + grade);
   }
}

Java String toUpperCase() and toLowerCase() methods

java8

import java.lang.*;
public class StringDemo {
   public static void main(String[] args) {
      // converts all upper case letters in to lower case letters
      String str1 = "SELF LEARNING CENTER";
      System.out.println("string value = " + str1.toLowerCase());
      str1 = "TUTORIALS POINT";
      System.out.println("string value = " + str1.toLowerCase());
      
      // converts all lower case letters in to upper case letters
      String str2 = "This is TutorialsPoint";
      System.out.println("string value = " + str2.toUpperCase());
      str2 = "www.tutorialspoint.com";
      System.out.println("string value = " + str2.toUpperCase());
   }
}

Correct way to trim a string in Java

java8

import java.lang.*;
public class StringDemo {
   public static void main(String[] args) {
      // string with leading and trailing white space
      String str = " This is TutorialsPoint ";
      System.out.print("Before trim = ");
      System.out.println(".." + str + "..");
      
      // leading and trailing white space removed
      System.out.print("After trim = ");
      System.out.println(".." + str.trim() + "..");
   }
}

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