OutOfMemoryError for some loci while getting the sorted iterator for BAM files

Exception in thread "Thread-39914" java.lang.OutOfMemoryError: GC overhead limit exceeded
	at net.sf.samtools.BAMRecordCodec.decode(BAMRecordCodec.java:199)
	at net.sf.samtools.BAMFileReader$BAMFileIterator.getNextRecord(BAMFileReader.java:557)
	at net.sf.samtools.BAMFileReader$BAMFileIndexIterator.getNextRecord(BAMFileReader.java:664)
	at net.sf.samtools.BAMFileReader$BAMFileIterator.advance(BAMFileReader.java:531)
	at net.sf.samtools.BAMFileReader$BAMFileIterator.next(BAMFileReader.java:521)
	at net.sf.samtools.BAMFileReader$BAMFileIterator.next(BAMFileReader.java:480)
	at net.sf.samtools.BAMFileReader$BAMQueryFilteringIterator.advance(BAMFileReader.java:749)
	at net.sf.samtools.BAMFileReader$BAMQueryFilteringIterator.next(BAMFileReader.java:719)
	at net.sf.samtools.BAMFileReader$BAMQueryFilteringIterator.next(BAMFileReader.java:672)
	at net.sf.samtools.SAMFileReader$AssertableIterator.next(SAMFileReader.java:664)
	at net.sf.samtools.SAMFileReader$AssertableIterator.next(SAMFileReader.java:642)
	at barna.io.sam.SAMMappingSortedIterator$1.run(SAMMappingSortedIterator.java:82)
	at java.lang.Thread.run(Thread.java:662)