Catalina.out file customization

Question

I need to combine the exceptions lines in the Catalina.out file. How would I do that?

For example :

Mar 13, 2015 10:31:46 AM org.apache.solr.common.SolrException log
SEVERE: null:java.lang.IndexOutOfBoundsException: toIndex = 140
        at java.util.ArrayList.subListRangeCheck(ArrayList.java:922)

I would like it like this: (In a single line)

Mar 13, 2015 10:31:46 AM org.apache.solr.common.SolrException log SEVERE: null:java.lang.IndexOutOfBoundsException: toIndex = 140
        at java.util.ArrayList.subListRangeCheck(ArrayList.java:922)
        at java.util.ArrayList.subList(ArrayList.java:914)

How would I customize the format of log entries. Currently, exceptions are logged over multiple lines which makes it hard to parse.