java.util.ArrayList throwing IndexOutOfBounds exception

Question

I came across the following trace today:

java.lang.IndexOutOfBoundsException: Index: 2, Size: 2
    at java.util.ArrayList.rangeCheck(ArrayList.java:635)
    at java.util.ArrayList.get(ArrayList.java:411)
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1720)
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:500)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:388)
    at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:273)
    at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:96)
    at [.. somewhere in my code]

During that time the system was very busy and I guess also strained for memory and I was also experiencing some heap exhaustion errors ( java.lang.OutOfMemoryError: Java heap space ). Since the above trace came out of the guts of system / PostgreSQL / Apache libraries is it likely that a system very low on memory could trigger it?

It doesn't look like an issue in my code or the trace wouldn't have been so deep, right?

Answer 1

ArrayLists use zero-based indexes, the index 2 is invalid in a list of length 2 (the information given in your trace). It is probably an issue in your code that was passed through the query engine until it triggered the exception.