Fixed regex for java version
The current Sed does not correctly handle java version strings that only include the major version:
```
echo "openjdk version "16" 2021-03-16" | java -version 2>&1 | head -n 1 | cut -d'"' -f2 | sed -E 's/^(foo)?([0-9]+).+$/\2/'
1
```
The fix is to change the regex from `+` to `*`:
```
$ echo "openjdk version "16" 2021-03-16" | java -version 2>&1 | head -n 1 | cut -d'"' -f2 | sed -E 's/^(foo)?([0-9]+).*$/\2/'
16
```
diff --git a/jaxb-ri/bundles/ri/src/main/resources/bin/xjc.sh b/jaxb-ri/bundles/ri/src/main/resources/bin/xjc.sh
index fbceb23..433a8ea 100755
--- a/jaxb-ri/bundles/ri/src/main/resources/bin/xjc.sh
+++ b/jaxb-ri/bundles/ri/src/main/resources/bin/xjc.sh
@@ -67,7 +67,7 @@
unset JAVA_TOOL_OPTIONS
fi
-JAVA_VERSION=$("$JAVA" -version 2>&1 | head -n 1 | cut -d'"' -f2 | sed -E 's/^(1\.)?([0-9]+).+$/\2/')
+JAVA_VERSION=$("$JAVA" -version 2>&1 | head -n 1 | cut -d'"' -f2 | sed -E 's/^(1\.)?([0-9]+).*$/\2/')
echo "Java major version: ${JAVA_VERSION}"
if [ -n "$_OPTS" ]
