5 Examples Of Substring() Inwards Java

SubString inward Java is a useful method from java.lang.String class, which is used to create smaller String from bigger ones. The way Substring plant prior to Java 1.7 tin create a subtle retention leak because both String and their substring shares same grapheme array. Which means, if you lot receive got a large String of 200MB in addition to created a substring of 2MB from that, that could prevent 200MB String from beingness garbage collected. I concord this doesn't facial expression normal in addition to indeed was a bug, but it was similar that till Java 1.6 in addition to it's diverse update. One reason, which I could think, why Java designer initially idea similar that, perchance to relieve retention past times sharing char array in addition to to make, creating substring faster past times simply copying pointers, instead of data. Nevertheless, this was reported equally põrnikas in addition to Oracle have fixed it, hence no to a greater extent than substring retention leak issue inward Java 7.


This number doesn't undermine the importance of substring method, which is 1 of the most useful methods from java.lang.String class. One thing, which is likewise worth remembering is that, whenever you lot telephone outcry upward substring method, it supply a separate String object, because String is immutable inward Java. In side past times side section, nosotros volition encounter the syntax of substring method in addition to How to usage it for practical purpose.

SubString inward Java - Description, Syntax in addition to Example

Substring method is overloaded inward Java, in addition to nosotros receive got 2 variants of it, kickoff receive got 1 parameter, simply laid out index in addition to instant receive got 2 parameters, laid out index in addition to terminate index equally shown below:

public String substring(int beginIndex) public String substring(int beginIndex, int endIndex)

In the instance of the kickoff method, substring starts alongside beginIndex in addition to goes till the terminate of String, while, inward the instance of an overloaded  method, substring starts from beginIndex in addition to goes till endIndex -1. Since String inward Java is nada indexes based,  beginIndex can hold out from 0 to length of String. Let's encounter couplet of examples of substring method to larn how they work:

public class SubStringTest {      public static void main(String[] args) {      String quote = "Java is to JavaScript what Car is to Carpet";                                                                            // Example 1 - Let's say, nosotros take alone "what Car is to Carpet" substring         // out start volition hold out 22, you lot tin likewise exercise quote.indexOf("what")       // in addition to nosotros tin kickoff substring method                                                                                                      String substr = quote.substring(22);                                 System.out.println(substr);                                                                                                               // Example 2 - Let's say, nosotros take "Java" from quote                              // start volition hold out 0 in addition to terminate volition hold out four (because terminate is exclusive)                                                                           String substr2 = quote.substring(0,4);                               System.out.println(substr2);                                                                                                              // Example iii - Following telephone outcry upward to substring method volition supply empty String     String substr3 = quote.substring(quote.length());                    System.out.println(substr3.isEmpty());                                                                                                    // Example four - substring method volition likewise supply empty String if laid out = terminate     String substr4 = quote.substring(3,3);                               System.out.println(substr4.isEmpty());                                                                                                    // Example v - This substring telephone outcry upward volition throw IndexOutOfBoundException           String substr5 = quote.substring(-1);  // start < 0                  String substr6 = quote.substring(2,1); // start > terminate                      }  }

Output  what Car is to Carpet Java true true Exception inward thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1  at java.lang.String.substring(Unknown Source)  at java.lang.String.substring(Unknown Source)

Remember substring(int beginIndex) method volition throw IndexOutOfBoundException if, an index is less than nada or to a greater extent than than length of String. While substring(int beginIndex, int endIndex) volition throw IndexOutOfBoundException if beginIndex is negative, or larger than endIndex or end > length().

It's likewise worth knowing that substring volition supply empty String if you lot travel past times the length of String equally a start inward the kickoff version in addition to same index equally start in addition to terminate inward the instant method, equally shown inward our substring illustration inward Java.

Important points almost substring() inward Java

1. There are 2 substring() method, kickoff receive got alone starting signal spell instant await both starting in addition to terminate points.
   

   public String substring(int beginIndex) public String substring(int beginIndex, int endIndex)

2. The string starts alongside index 0 i.e. kickoff grapheme volition hold out at index 0. So if you lot desire to take away the kickoff character, simply exercise substring(1), it volition supply substring without kickoff character, equal to deleting the kickoff character.
3. In the instant method, startIndex is inclusive but endIndex is exclusive, which way if you lot desire to take away the concluding grapheme hence you lot take to laissez passer on substring(0, string.length()-1).
4. The substring() method volition supply an empty String if beginIndex= endIndex.
5. The substring() method volition throw IndexOutOfBoundsException if start < 0 or start > end.

in addition to hither is a squeamish summary slide of all the of import things you lot learned almost the substring() method inward this article past times doing those examples:

That's all almost substring inward Java. nosotros receive got seen How to usage substring to create smaller String from a large text. We receive got likewise compared 2 overloaded version of substring past times unlike substring examples, in addition to likewise touched based on memory leak issue due to substring, which is straightaway fixed inward JDK 1.7.

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