No matter what pattern I build the RE.matchNodes() method throws an array index out of bounds exception. I am using v1.2 from the web site. One pattern I am trying is "^interface Serial./." . I have passed the match() method various strings to compare including an empty string, a string containing just a new line, and full strings. The result is always the same. STACK TRACE: java.lang.ArrayIndexOutOfBoundsException at org.apache.regexp.RE.matchNodes(RE.java:859) at org.apache.regexp.RE.matchAt(RE.java:1448) at org.apache.regexp.RE.match(RE.java:1498) at org.apache.regexp.RE.match(RE.java:1468) at CompareAll.main(CompareAll.java:847) Operating system: Windows NT 4.00.1381 , service pack 6 Java Virtual Machine: 1.3.1 Al