Android, java String.trim() throws ArrayIndexOutOfBoundsException

Question

Analyzing my Android app crashes, I found a weird one that happens only on Samsung Galaxy Note 3 devices. Here is the top of crash stack:

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java.lang.ArrayIndexOutOfBoundsException
java.lang.String.trim(String.java:1416)
-------

Does anyone know how it can be possible?

It looks like manufacturer slightly updated original version of String class.

Comment: The problem is that String object is immutable - I can not modify internal chars array or string length in any way. That's why trim() method in theory should never throw such type of exceptions: trim() method must check array bounds by itself (that it really does in default implementation).

you access extra array index which is not present ........... — sushildlh, May 19 '16 at 06:31
Yes, trim() method works fine on other devices.The problem is that java String is immutable, so I just can not access extra array index by invoking trim() method. — Artem, May 19 '16 at 06:39

score 0 · Answer 1 · answered May 19 '16 at 06:44

You might need to make your own version of trim() if you want to ensure that it is 100% vendor-independent.

Here's what the Oracle JDK version of trim() looks like:

public String trim() {
    int len = value.length;
    int st = 0;
    char[] val = value;    /* avoid getfield opcode */

    while ((st < len) && (val[st] <= ' ')) {
        st++;
    }
    while ((st < len) && (val[len - 1] <= ' ')) {
        len--;
    }
    return ((st > 0) || (len < value.length)) ? substring(st, len) : this;
}

The value in the above fragment is the char[] of the String

Probably I will. I just want to make sure I didn't miss anything. — Artem, May 19 '16 at 06:53

Android, java String.trim() throws ArrayIndexOutOfBoundsException

1 Answers1