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Page 200 of 589
Function pointers in Java
From Java 8 onwards, the lambda expression is introduced which acts as function pointers.Lambda expressions are introduced in Java 8 and are touted to be the biggest feature of Java 8. Lambda expression facilitates functional programming and simplifies the development a lot.SyntaxA lambda expression is characterized by the following syntax.parameter -> expression bodyFollowing are the important characteristics of a lambda expression.Optional type declaration − No need to declare the type of a parameter. The compiler can inference the same from the value of the parameter.Optional parenthesis around parameter − No need to declare a single parameter in parenthesis. For multiple ...
Read MoreSearch and Replace with Java regular expressions
Java provides the java.util.regex package for pattern matching with regular expressions. Java regular expressions are very similar to the Perl programming language and very easy to learn.A regular expression is a special sequence of characters that help you match or find other strings or sets of strings, using a specialized syntax held in a pattern. They can be used to search, edit, or manipulate text and data.The replaceFirst() and replaceAll() methods replace the text that matches a given regular expression. As their names indicate, replaceFirst replaces the first occurrence, and replaceAll replaces all occurrences.Exampleimport java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexMatches { ...
Read MoreHow to split a Java String into tokens with StringTokenizer?
The hasMoreTokens() method is used to test if there are more tokens available from this tokenizer's string.Exampleimport java.util.*; public class StringTokenizerDemo { public static void main(String[] args) { // creating string tokenizer StringTokenizer st = new StringTokenizer("Come to learn"); // checking elements while (st.hasMoreElements()) { System.out.println("Next element : " + st.nextElement()); } } }OutputNext element : Come Next element : to Next element : learn
Read MoreHow to check if a String contains another String in a case insensitive manner in Java?
One way to do it to convert both strings to lower or upper case using toLowerCase() or toUpperCase() methods and test.Examplepublic class Sample { public static void main(String args[]){ String str = "Hello how are you welcome to Tutorialspoint"; String test = "tutorialspoint"; Boolean bool = str.toLowerCase().contains(test.toLowerCase()); System.out.println(bool); } }Outputtrue
Read MoreWrite a java program to tOGGLE each word in string?
You can change the cases of the letters of a word using toUpperCase() and toLowerCase() methods.Split each word in the string using the split() method, change the first letter of each word to lower case and remaining letters to upper case.Examplepublic class Sample{ public static void main(String args[]){ String sample = "Hello How are you"; String[] words = sample.split(" "); String result = ""; for(String word:words){ String firstSub = word.substring(0, 1); String secondSub = word.substring(1); result = result+firstSub.toLowerCase()+secondSub.toUpperCase()+" "; } System.out.println(result); } }OutputhELLO hOW aRE yOU
Read MoreStringTokenizer class in Java
The StringTokenizer class of the java.util package allows an application to break a string into tokens.This class is a legacy class that is retained for compatibility reasons although its use is discouraged in new code.Its methods do not distinguish among identifiers, numbers, and quoted strings.This class methods do not even recognize and skip comments.Exampleimport java.util.*; public class Sample { public static void main(String[] args) { // creating string tokenizer StringTokenizer st = new StringTokenizer("Come to learn"); // checking next token System.out.println("Next token is : " + st.nextToken()); } }OutputNext token is : Come
Read MoreJava String toCharArray() method example.
The toCharArray() method of a String class converts this string to a character array.Exampleimport java.lang.*; public class StringDemo { public static void main(String[] args) { // converts String value to character array type value String str = " Java was developed by James Gosling"; char retval[] = str.toCharArray(); // displays the converted value System.out.println("Converted value to character array = "); System.out.println(retval); } }OutputConverted value to character array = Java was developed by James Gosling
Read MoreHow to test String is null or empty?
We can verify whether the given string is empty using the isEmpty() method of the String class. This method returns true only if length() is 0.Exampleimport java.lang.*; public class StringDemo { public static void main(String[] args) { String str = "tutorialspoint"; // prints length of string System.out.println("length of string = " + str.length()); // checks if the string is empty or not System.out.println("is this string empty? = " + str.isEmpty()); } }Outputlength of string = 14 is this string empty? = false
Read MoreHow to Split a String with Escaped Delimiters?
The split(String regex) method of the String class splits this string around matches of the given regular expression.Examplepublic class Sample{ public static void main(String args[]){ String s = "|A|BB||CCC|||"; String[] words = s.split("\|"); for (String string : words) { System.out.println(string); } } }OutputA BB CCC
Read MoreJava string case change sample code examples.
You can change the cases using the toUpperCase() and toLowerCase() methods of the String class.Examplepublic class Sample { public static void main(String args[]){ String str = "Hello how are you"; String strUpper = str.toUpperCase(); System.out.println("Lower to upper : "+strUpper); String strLower = str.toLowerCase(); System.out.println("Upper to lower : "+strLower); } }OutputLower to upper : HELLO HOW ARE YOU Upper to lower : hello how are you
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