The java.lang.StringIndexOutOfBoundsException is RuntimeException or Checked Exception which is thrown by the methods of String class during index operations which indicate accessing index is either negative or greater than size of string itself.
java.lang.StringIndexOutOfBoundException is subclass of the IndexOutOfBoundException class which is used to indicate that accessing index to either an Array, Vector or String, is out of Range.
String Class Methods where StringIndexOutOfBoundsException happen:
String object index range is between 0 to String.length() -1 if object access beyond this range lower or greater will throw StringIndexOutOfBoundsException .
- public char charAt(int index);
- public String substring(beginIndex);
- public String subString(beginIndex,endIndex);
- public CharSequence subSequence(beginIndex,endIndex);
- public static String valueOf(char[] data, int offset, int count)
Example : Below example is for print all possible SubString for String FacingIssuesOnIT will throw StringIndexOutOfBoundException. on run time because index conditions are not properly handled.
package example;
public class StringIndexOutOfBounExceptionExample {
public static void main(String[] args) {
String str = "FacingIssueOnIT";
System.out.println("*********All Substring of FacingIssuesonIT");
for (int i = 0; i <= str.length(); i++) {
for (int j = i + 1; j <= str.length(); j++) {
System.out.println(str.substring(i, j - i));
}
}
}
}
Output :
*********All Substring of FacingIssuesonIT F Fa Fac Faci Facin Facing FacingI FacingIs FacingIss FacingIssu FacingIssue FacingIssueO FacingIssueOn FacingIssueOnI a ac aci acin acing acingI acingIs acingIss acingIssu acingIssue acingIssueO acingIssueOn Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1 at java.lang.String.substring(Unknown Source) at example.StringIndexOutOfBounExceptionExample.main(StringIndexOutOfBounExceptionExample.java:10)
Issues with above Example :
Actually, your right edge of your substring function may be lower than the left one. For example, when i=(size-1) and j=size, you are going to compute substring(size-1, 1). This is the cause of you error.
Modified Example:
When you compare with above example loop condition are change SubString above range selection is modified.
package example;
public class StringIndexOutOfBounExceptionExample {
public static void main(String[] args) {
String str = "FacingIssueOnIT";
System.out.println("*********All Substring of FacingIssuesOnIT");
for (int i = 0; i <=str.length()-1; i++) {
for (int j = i+1 ; j <= str.length(); j++) {
//System.out.println("i="+i+",j="+ j);
System.out.println(str.substring(i, j));
}
}
}
}
Output:
*********All Substring of FacingIssuesOnIT F Fa Fac Faci Facin Facing FacingI FacingIs FacingIss FacingIssu FacingIssue FacingIssueO FacingIssueOn FacingIssueOnI FacingIssueOnIT a ac aci acin acing acingI acingIs acingIss acingIssu acingIssue acingIssueO acingIssueOn acingIssueOnI acingIssueOnIT c ci cin cing cingI cingIs cingIss cingIssu cingIssue cingIssueO cingIssueOn cingIssueOnI cingIssueOnIT i in ing ingI ingIs ingIss ingIssu ingIssue ingIssueO ingIssueOn ingIssueOnI ingIssueOnIT n ng ngI ngIs ngIss ngIssu ngIssue ngIssueO ngIssueOn ngIssueOnI ngIssueOnIT g gI gIs gIss gIssu gIssue gIssueO gIssueOn gIssueOnI gIssueOnIT I Is Iss Issu Issue IssueO IssueOn IssueOnI IssueOnIT s ss ssu ssue ssueO ssueOn ssueOnI ssueOnIT s su sue sueO sueOn sueOnI sueOnIT u ue ueO ueOn ueOnI ueOnIT e eO eOn eOnI eOnIT O On OnI OnIT n nI nIT I IT T
How to avoid StringIndexOutOfBoundException?
- Debug program throughly after printing index values.
- During operation check index value range between 0 to String.length()-1.
Facing Issues On IT 