$re = '/.*<!\[CDATA\[00000:([\w\W]*?)\]\]>.*/';
$str = 'String srcMsg="<?xml version=\\"1.0\\" encoding=\\"UTF-8\\"?>\\n<root><resultCode>00000</resultCode><resultDesc>
<![CDATA[00000:<ResponseClass Name=\\"Response\\">\\n <ResponseSubClass Name=\\"attributesResponse\\">\\n
<ITEM>0</ITEM>\\n </ResponseSubClass>\\n</ResponseClass>]]></resultDesc></root>";
//The right code
java.util.regex.Pattern pP0 = java.util.regex.Pattern.compile(".*<!\\\\[CDATA\\\\[00000:((.|\\n)*)\\\\]\\\\]>.*");
//wrong code1
//java.util.regex.Pattern pP0 = java.util.regex.Pattern.compile(".*<!\\\\[CDATA\\\\[00000:(\\\\s|\\\\S)*\\\\]\\\\]>.*");
//wrong code2
//java.util.regex.Pattern pP0 = java.util.regex.Pattern.compile(".*<!\\\\[CDATA\\\\[00000:[\\\\w|\\\\W]*\\\\]\\\\]>.*");
java
<![CDATA[00000: asdfasdf
sssdgasgf
asfgas
]]>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php