![]() Let’s try out what you’ve learned about the String class in a quick challenge.įor this challenge, you’ll compare a number of Strings using the concepts we’ve explored. Verifies if there is a specified CharSequence in the String ReplaceAll(String regex, String replacement) Returns the characters length of the String Consider these common methods of the String class: There’s just one last thing you need to know before taking the String comparison challenge. It doesn’t matter if the object reference is different the state of the String will be compared. : StringUTF16.equals(value, aString.value) Īs you can see, the state of the String class value has to be equals() and not the object reference. Return isLatin1() ? StringLatin1.equals(value, aString.value) But the equals() method has to be overridden to make it work properly. Because equals() is from the Object class, every Java class inherits it. Syntax: int indexOf (char ch ) Parameters: ch : a character. This article depicts about all of them, as follows: 1.int indexOf () : This method returns the index within this string of the first occurrence of the specified character or -1, if the character does not occur. The equals() method is used to verify if the state of two Java classes are the same. Java String indexOf () There are four variants of indexOf () method. That’s because using the intern() method ensures the Strings will be stored in the pool. Unlike the previous example with the new keyword, in this case the comparison turns out to be true. (duke.intern() = duke2.intern()) // The result will be true here (duke = duke2) // The result will be false here Now, notice what happens when we use the new keyword to force the creation of two Strings: Behind the scenes, the logic of String pooling is based on the Flyweight pattern. If not, it creates a new String in the pool. First, it verifies if the String you’ve created already exists in the pool. The intern() method is used to store Strings in a String pool. * guaranteed to be from a pool of unique strings. * a string that has the same contents as this string, but is String literals are defined in section 3.10.5 of the * All literal strings and string-valued constant expressions are Public String(char value, int offset, int count). Overloading can make your classes really flexible, including String: My first blog in the Java Challengers series introduced method overloading, which is a technique the String class uses extensively. It’s the same in object-oriented programming. ![]() Each of these interfaces supports certain actions: accelerate, brake, turn left, turn right. Do you need to know how the car works under the hood in order to drive it? Of course not, but you do need to know what the interfaces of the car do: things like the accelerator, brakes, and steering wheel. To understand encapsulation better, consider a physical object: a car. ![]() When you look at the String class in Java, you can see how the array of char is encapsulated: Because of encapsulation, you don’t need to know how the String class works you just need to know what methods to use on its interface. Put simply, String is an array of characters used to compose words, sentences, or any other data you want.Įncapsulation is one of the most powerful concepts in object-oriented programming. In Java, the String class encapsulates an array of char.
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