FULL PRODUCT VERSION :
sun-jdk-8u51

ADDITIONAL OS VERSION INFORMATION :
Linux checker 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2+deb8u3 (2016-07-02) x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
If you call Scanner.nextInt(int) with a parameter < 2, you get a PatternSyntaxException, which is not a documented output.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
http://ideone.com/iuW4K0

new Scanner("").nextInt(0);

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Some sort of exception saying "radix must be >= 2".
ACTUAL -
Exception in thread "main" java.util.regex.PatternSyntaxException: Unclosed character class near index 525
(([-+]?(((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))))|(((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))|(\Q-\E((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             ^
at java.util.regex.Pattern.error(Pattern.java:1955)
at java.util.regex.Pattern.clazz(Pattern.java:2548)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.sequence(Pattern.java:2063)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.compile(Pattern.java:1696)
at java.util.regex.Pattern.<init>(Pattern.java:1351)
at java.util.regex.Pattern.compile(Pattern.java:1028)
at java.util.Scanner$1.create(Scanner.java:367)
at java.util.Scanner$1.create(Scanner.java:365)
at sun.misc.LRUCache.forName(LRUCache.java:72)
at java.util.Scanner.integerPattern(Scanner.java:443)
at java.util.Scanner.nextInt(Scanner.java:2117)
at Ideone.main(Main.java:12)

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.util.regex.PatternSyntaxException: Unclosed character class near index 525
(([-+]?(((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))))|(((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))|(\Q-\E((((?i)[]|\p{javaDigit})++)|([\p{javaDigit}&&[^0]]((?i)[]|\p{javaDigit})?((?i)[]|\p{javaDigit})?(\,((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit})((?i)[]|\p{javaDigit}))+)))
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             ^
at java.util.regex.Pattern.error(Pattern.java:1955)
at java.util.regex.Pattern.clazz(Pattern.java:2548)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.clazz(Pattern.java:2504)
at java.util.regex.Pattern.sequence(Pattern.java:2063)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.group0(Pattern.java:2905)
at java.util.regex.Pattern.sequence(Pattern.java:2051)
at java.util.regex.Pattern.expr(Pattern.java:1996)
at java.util.regex.Pattern.compile(Pattern.java:1696)
at java.util.regex.Pattern.<init>(Pattern.java:1351)
at java.util.regex.Pattern.compile(Pattern.java:1028)
at java.util.Scanner$1.create(Scanner.java:367)
at java.util.Scanner$1.create(Scanner.java:365)
at sun.misc.LRUCache.forName(LRUCache.java:72)
at java.util.Scanner.integerPattern(Scanner.java:443)
at java.util.Scanner.nextInt(Scanner.java:2117)
at Ideone.main(Main.java:12)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
public static void main (String[] args) throws java.lang.Exception
{
new Scanner("").nextInt(0);
}
}
---------- END SOURCE ----------