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Articles on Trending Technologies
Technical articles with clear explanations and examples
Get the substring after the first occurrence of a separator in Java
We have the following string with a separator.String str = "Tom-Hanks";We want the substring after the first occurrence of the separator i.e.HanksFor that, first you need to get the index of the separator and then using the substring() method get, the substring after the separator.String separator ="-"; int sepPos = str.indexOf(separator); System.out.println("Substring after separator = "+str.substring(sepPos + separator.length()));The following is an example.Examplepublic class Demo { public static void main(String[] args) { String str = "Tom-Hanks"; String separator ="-"; int sepPos = str.indexOf(separator); if (sepPos == -1) { ...
Read MoreJava Program to subtract long integers and check for overflow
To check for Long overflow, we need to check the Long.MAX_VALUE with the subtracted long result. Here, Long.MAX_VALUE is the maximum value of Long type in Java.Let us see an example wherein long integers are subtracted and if the result is still more than the Long.MAX_VALUE, then an exception is thrown −The following is an example showing how to check for Long overflow −Examplepublic class Demo { public static void main(String[] args) { long val1 = 70123; long val2 = 10567; ...
Read MoreJava Program to convert an int to a boolean specifying the conversion values
To convert int to boolean, let us first take the following int.int one = 1; int two = 1; int three = 0;We have nested if-else statement to display the true or false values. Here, the value “one” is the same as “two” i.e. 1; therefore, the following works −else if (one.equals(two)) { System.out.println(true); }The above display “true” and in this way we converted int to boolean.Let us now see the complete example to learn how to convert int to Boolean.Examplepublic class Demo { public static void main(String[] args) { int one = 1; ...
Read MoreGet the substring before the last occurrence of a separator in Java
We have the following string with a separator.String str = "David-Warner";We want the substring before the last occurrence of a separator. Use the lastIndexOf() method.For that, you need to get the index of the separator using indexOf()String separator ="-"; int sepPos = str.lastIndexOf(separator); System.out.println("Substring before last separator = "+str.substring(0, sepPos));The following is an example.Examplepublic class Demo { public static void main(String[] args) { String str = "David-Warner"; String separator ="-"; int sepPos = str.lastIndexOf(separator); if (sepPos == -1) { System.out.println(""); ...
Read MoreConvert Long to numeric primitive data types in Java
Let’s say we have Long object here.Long myObj = new Long("9879");Now, if we want to convert this Long to short primitive data type. For that, use the in-built shortValue() method −// converting to short primitive types short shortObj = myObj.shortValue(); System.out.println(shortObj);In the same way convert Long to another numeric primitive data type int. For that, use the in-built intValue() method −// converting to int primitive types int intObj = myObj.intValue(); System.out.println(intObj);The following is an example wherein we convert Long to numeric primitive types short, int, float, etc −Examplepublic class Demo { public static void main(String[] args) { ...
Read MoreCount how many times the substring appears in the larger String in Java
Let’s say we have the following string.String str = "Learning never ends! Learning never stops!";In the above string, we need to find out how many times the substring “Learning” appears.For this, loop until the index is not equal to 1 and calculate.while ((index = str.indexOf(subString, index)) != -1) { subStrCount++; index = index + subString.length(); }The following is an example.Examplepublic class Demo { public static void main(String[] args) { String str = "Learning never ends! Learning never stops!"; System.out.println("String: "+str); int subStrCount = 0; String subString = ...
Read MoreCreate a StringBuffer object using a reference stored in a variable of type String in Java
To create a StringBuffer Object, we use the following syntax −StringBuffer s=new StringBuffer();When we create a reference to an object, we use the assignment operator. For example, String s1 = ”hi”; String s2 = s1; // s2 is a reference of s1A program to illustrate the creation of a StringBuffer object using a reference stored in a variable of type String is given below −Examplepublic class Example { public static void main(String args[]) { String input = "hey"; String s1 = input; // creating a reference of the String StringBuffer ...
Read MoreJava Program to display double and single quote in a string
The following are our strings with single and double quote.String str1 = "This is Jack's mobile"; String str2 = ""This is it"!";Above, for single quote, we have to mention it normally like.This is Jack's mobileHowever, for double quotes, use the following and add a slash in the beginning as well as at the end.String str2 = ""This is it"!";The following is an example.Examplepublic class Demo { public static void main(String[] args) { String str1 = "This is Jack's mobile"; String str2 = ""This is it"!"; System.out.println("Displaying Single Quote: "+str1); ...
Read MoreRandom vs Secure Random numbers in Java
Java provides two classes for having random numbers generation - SecureRandom.java and Random.java.The random numbers can be used generally for encryption key or session key or simply password on web server.SecureRandom is under java.security package while Random.java comes under java.util package.The basic and important difference between both is SecureRandom generate more non predictable random numbers as it implements Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) as compare to Random class which uses Linear Congruential Generator (LCG).A important point to mention here is SecureRandom is subclass of Random class and inherits its all method such as nextBoolean(), nextDouble(), nextFloat(), nextGaussian(), nextInt() and ...
Read MoreJava Program to check for Integer overflow
To check for Integer overflow, we need to check the Integer.MAX_VALUE, which is the maximum value of an integer in Java.Let us see an example wherein integers are added and if the sum is more than the Integer.MAX_VALUE, then an exception is thrown.Examplepublic class Demo { public static void main(String[] args) { int val1 = 9898989; int val2 = 6789054; System.out.println("Value1: "+val1); System.out.println("Value2: "+val2); long sum = (long)val1 + (long)val2; if (sum > Integer.MAX_VALUE) { throw new ...
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