String index out of bounds exception java

Question

I am getting the following error when calling a function from within my class: java.lang.StringIndexOutOfBoundsException: String index out of range: -1. Although I used a system prints to see the inputs I am passing in the substring() function and everything seems to be right. The function isContained() returns a boolean value defining whether the substring passed as a parameter is in a list of words. My code is:

for(int i=0; i<=size; i++)
    for(int j=i+1; j<=size; j++)
        if(isContained(str.substring(i,j-i)))
            System.out.println(str.substring(i,j-i));

where size is the size of the string (str) I am passing in the function

I don't think the problem is there fly. The error comes up for i=1.. — Rakim
– Rakim, Commented Nov 23, 2013 at 12:21
Try to Debug your program. Put printouts(i could read that you already tried that), so use a Debugger. If you are using Eclipse IDE it has a built in Debugger. — Gábor Csikós
– Gábor Csikós, Commented Nov 23, 2013 at 12:21

Pshemo · Accepted Answer · 2025-11-24 20:23:58Z

7

You are calling str.substring(i, j-i) which means substring(beginIndex, endIndex), not substring(beginIndex, lengthOfNewString).

In documentation of this method we can read (emphasis mine):

Throws:
IndexOutOfBoundsException - if the beginIndex is negative, or endIndex is larger than the length of this String object, or beginIndex is larger than endIndex.

So endIndex must be greater or equal to beginIndex. If that assumption is not fulfilled method throws StringIndexOutOfBoundsException (which is subclass of IndexOutOfBoundsException).

If I understand your example correctly you should change it to str.substring(i, j).

Also if size is length of your str then

for (int i = 0; i <= size; i++)

should most likely be

for (int i = 0; i < size; i++)

edited 17 hours ago

answered Nov 23, 2013 at 12:22

Pshemo

125k25 gold badges194 silver badges280 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Rakim Over a year ago

You are right... I thought the method was accepting (index, length)

SASM · Accepted Answer · 2013-11-23 12:23:56Z

0

I think you need to change the looping condition which is the problem here. You are looping one more iteration when you do <=size and the index starts from i=0. You can change this

for(int i=0; i<=size; i++)

to

for(int i=0; i<size; i++)

and also take care about the inner loop condition.

answered Nov 23, 2013 at 12:23

SASM

1,3101 gold badge22 silver badges44 bronze badges

1 Comment

SASM Over a year ago

Why negative voting here?

alex2410 · Accepted Answer · 2013-11-23 12:55:00Z

0

IndexOutOfBoundsException -- if the beginIndex is negative, or endIndex is larger than the length of this String object, or beginIndex is larger than endIndex.

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.

edited Nov 23, 2013 at 12:55

alex2410

11k3 gold badges29 silver badges41 bronze badges

answered Nov 23, 2013 at 12:31

Besoul

356 bronze badges

Collectives™ on Stack Overflow

String index out of bounds exception java

3 Answers 3

1 Comment

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related