String intern() Returns a canonical representation for the string object. int indexOf(String str, int fromIndex) Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. int indexOf(String str) Returns the index within this string of the first occurrence of the specified substring. int indexOf(int ch, int fromIndex) Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index. int indexOf(int ch) Returns the index within this string of the first occurrence of the specified character.
Java string code#
int hashCode() Returns a hash code for this string. void getChars(int srcBegin, int srcEnd, char dst, int dstBegin) Copies characters from this string into the destination character array. int compareToIgnoreCase(String str) Compares two strings lexicographically, ignoring case differences. int compareTo(String anotherString) Compares two strings lexicographically. int compareTo(Object o) Compares this String to another Object. The class provides many useful methods for dealing with a sequence of char values: Method Description char charAt(int index) Returns the character at the specified index. String in Java is a sequence of char valuesĪ String is actually an array of characters. The difference between creating a String with a literal and a new keyword is that if we use a String literal, the JVM will use a String pool and save a lot of memory and increase performance, while with the new keyword it will create a new object in Java heap memory each time, which is a significantly expensive operation.
Then, we compare str1 and str3, and we get false because they are two different objects.We compare str1 and str2, and we get true because both strings point to the same object.After that, we create a new String str3 by instantiating it with the keyword new, a new object is created, and it will be outside the String pool part.The existing String literal from the String pool will be used. Then, we create a new String str2 and assign it the same literal.Then, that value goes to the String pool. We create str1 by assigning it a String literal.Since creating a new String is costly in both the cases of time and memory, the JVM keeps a pool of strings.Ī String pool allows JVM to save memory by preserving immutable strings in a pool so that the application can reuse instances of common strings instead of creating multiple instances. String pool is a storage area in the Java heap memory part. To create a String, we can instantiate it, just like any other class in Java: String str = new String("Hello") įirst, let’s understand what a String pool is. When creating a new String, we assign it a value within double quotes: String str = "Hello" Whenever a change to a String is made, an entirely new String gets created. A String in Java is an object that represents an array of characters.
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