Need help in stringObj.replaceAll()

[Babar Qadri]

This line of code giving me errors.

"^(19|20)\\d{2}$".replaceAll("\\", "\\\\");
 
Exception:
 
java.util.regex.PatternSyntaxException: Unexpected internal error near index 1
\
 ^
java.util.regex.Pattern.error(Pattern.java:1528)
java.util.regex.Pattern.compile(Pattern.java:1286)
java.util.regex.Pattern.<init>(Pattern.java:1035)
java.util.regex.Pattern.compile(Pattern.java:779)
java.lang.String.replaceAll(String.java:1663)
shma.codevision.validator.UIValidatorScript.writeJavaScriptParams(UIValidatorScript.java:179)
shma.codevision.validator.UIValidatorScript.writeValidationFunctions(UIValidatorScript.java:135)
shma.codevision.validator.UIValidatorScript.encodeBegin(UIValidatorScript.java:212)
javax.faces.webapp.UIComponentTag.encodeBegin(UIComponentTag.java:591)
javax.faces.webapp.UIComponentTag.doStartTag(UIComponentTag.java:478)

I just want to replace single backslash with double. How to do that in a simple way. I have wrote a custom method to do this temporarily.

Please help me out folks.

[Jesper de Jong]

Backslash has a special meaning in Java source code, so you have to escape it by doubling it. But backspace also has a special meaning in regular expressions, so you have to double it again. Try this:

"^(19|20)\\d{2}$".replaceAll("\\\\", "\\\\\\\\");

[Jim Yingst]

If you're using JDK 5, you can use

"^(19|20)\\d{2}$".replace("\\", "\\\\");

See also a similar discussion here.

[Babar Qadri]

Thanks Jesper, its working.
Thanks Jim for a valuable information.