diff --git a/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java b/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java
index 5e6c08e73..fa746a7e3 100755
--- a/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java
+++ b/java/src/org/broadinstitute/sting/gatk/GenomeAnalysisEngine.java
@@ -123,6 +123,9 @@ public class GenomeAnalysisEngine {
      */
     public GenomeAnalysisEngine() {
         // make sure our instance variable points to this analysis engine
+//        if ( instance != null )
+//            throw new StingException("Instantiating GenomeAnalysisEngine but global instance variable isn't null, indicating that an instance has already been created: " + instance);
+
         instance = this;
         walkerManager = new WalkerManager();
         filterManager = new FilterManager();
@@ -736,7 +739,7 @@ public class GenomeAnalysisEngine {
 
             Shard.ShardType shardType;
             if(walker instanceof LocusWalker) {
-                if(readsDataSource != null && readsDataSource.getSortOrder() != SAMFileHeader.SortOrder.coordinate)
+                if (readsDataSource.getSortOrder() != SAMFileHeader.SortOrder.coordinate)
                     Utils.scareUser("Locus walkers can only walk over coordinate-sorted data.  Please resort your input BAM file.");                
                 shardType = Shard.ShardType.LOCUS;
             }
diff --git a/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantContextUtils.java b/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantContextUtils.java
index 57cc2e8f8..dd8d088b8 100755
--- a/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantContextUtils.java
+++ b/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantContextUtils.java
@@ -23,6 +23,7 @@
 
 package org.broadinstitute.sting.gatk.contexts.variantcontext;
 
+import java.io.Serializable;
 import java.util.*;
 import org.apache.commons.jexl2.*;
 import org.broadinstitute.sting.utils.StingException;
@@ -32,7 +33,7 @@ import org.broadinstitute.sting.utils.genotype.HardyWeinbergCalculation;
 import org.broad.tribble.vcf.VCFConstants;
 
 public class VariantContextUtils {
-    public static JexlEngine engine = new JexlEngine();
+    final public static JexlEngine engine = new JexlEngine();
 
     /** 
      * A simple but common wrapper for matching VariantContext objects using JEXL expressions
@@ -64,10 +65,10 @@ public class VariantContextUtils {
      */
     public static List<JexlVCMatchExp> initializeMatchExps(String[] names, String[] exps) {
         if ( names == null || exps == null )
-            throw new StingException("BUG: neither names nor exps can be null: names " + names + " exps=" + exps );
+            throw new StingException("BUG: neither names nor exps can be null: names " + Arrays.toString(names) + " exps=" + Arrays.toString(exps) );
 
         if ( names.length != exps.length )
-            throw new StingException("Inconsistent number of provided filter names and expressions: names=" + names + " exps=" + exps);
+            throw new StingException("Inconsistent number of provided filter names and expressions: names=" + Arrays.toString(names) + " exps=" + Arrays.toString(exps));
 
         Map<String, String> map = new HashMap<String, String>();
         for ( int i = 0; i < names.length; i++ ) { map.put(names[i], exps[i]); }
@@ -377,7 +378,7 @@ public class VariantContextUtils {
     }
 
 
-    static class CompareByPriority implements Comparator<VariantContext> {
+    static class CompareByPriority implements Comparator<VariantContext>, Serializable {
         List<String> priorityListOfVCs;
         public CompareByPriority(List<String> priorityListOfVCs) {
             this.priorityListOfVCs = priorityListOfVCs;
@@ -390,7 +391,7 @@ public class VariantContextUtils {
         }
 
         public int compare(VariantContext vc1, VariantContext vc2) {
-            return new Integer(getIndex(vc1)).compareTo(getIndex(vc2));
+            return Integer.valueOf(getIndex(vc1)).compareTo(getIndex(vc2));
         }
     }
 
diff --git a/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantJEXLContext.java b/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantJEXLContext.java
index ece9d8481..a0a90aef6 100644
--- a/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantJEXLContext.java
+++ b/java/src/org/broadinstitute/sting/gatk/contexts/variantcontext/VariantJEXLContext.java
@@ -35,6 +35,7 @@ import java.util.*;
 /**
  *
  * @author aaron
+ * @author depristo
  *
  * Class VariantJEXLContext
  *
@@ -42,12 +43,13 @@ import java.util.*;
  * having to generate a JEXML context lookup map everytime we want to evaluate an expression.
  *
  * This is package protected, only classes in variantcontext should have access to it.
+ *
+ * // todo -- clean up to remove or better support genotype filtering 
  */
 
 class VariantJEXLContext implements JexlContext {
     // our stored variant context
     private VariantContext vc;
-    private Genotype g;
 
     private interface AttributeGetter {
         public Object get(VariantContext vc);
@@ -71,16 +73,14 @@ class VariantJEXLContext implements JexlContext {
     }
 
     public VariantJEXLContext(VariantContext vc) {
-        this(vc, null);
-    }
-
-
-    public VariantJEXLContext(VariantContext vc, Genotype g) {
         this.vc = vc;
-        this.g = g;
-        //throw new UnsupportedOperationException("Cannot instantiate VariantJEXLContext");
     }
 
+//    public VariantJEXLContext(VariantContext vc, Genotype g) {
+//        this.vc = vc;
+//        //throw new UnsupportedOperationException("Cannot instantiate VariantJEXLContext");
+//    }
+
     public Object get(String name) {
         Object result = null;
         if ( x.containsKey(name) ) { // dynamic resolution of name -> value via map
@@ -155,12 +155,11 @@ class JEXLMap implements Map<VariantContextUtils.JexlVCMatchExp, Boolean> {
      * should get added.
      *
      */
-    private static final boolean USE_VCONTEXT = true;
     private void createContext() {
-        if ( USE_VCONTEXT && g == null ) {
-            jContext = new VariantJEXLContext(vc, g);
+        if ( g == null ) {
+            // todo -- remove dependancy on g to the entire system
+            jContext = new VariantJEXLContext(vc);
         } else {
-
             Map<String, Object> infoMap = new HashMap<String, Object>();
 
             if ( vc != null ) {
@@ -206,9 +205,6 @@ class JEXLMap implements Map<VariantContextUtils.JexlVCMatchExp, Boolean> {
             // create the internal context that we can evaluate expressions against
 
             jContext = new MapContext(infoMap);
-
-//            jContext = JexlHelper.createContext();
-//            jContext.setVars(infoMap);
         }
     }
 
diff --git a/java/src/org/broadinstitute/sting/gatk/filters/PlatformUnitFilterHelper.java b/java/src/org/broadinstitute/sting/gatk/filters/PlatformUnitFilterHelper.java
index 27ebbb623..383bf001b 100644
--- a/java/src/org/broadinstitute/sting/gatk/filters/PlatformUnitFilterHelper.java
+++ b/java/src/org/broadinstitute/sting/gatk/filters/PlatformUnitFilterHelper.java
@@ -63,8 +63,7 @@ import java.util.regex.Pattern;
  * To change this template use File | Settings | File Templates.
  */
 public class PlatformUnitFilterHelper {
-
-    public static Pattern EMPTYLINE_PATTERN = Pattern.compile("^\\s*$");
+    final public static Pattern EMPTYLINE_PATTERN = Pattern.compile("^\\s*$");
 
     public PlatformUnitFilterHelper(String arg) {
          File f = new File(arg);
diff --git a/java/src/org/broadinstitute/sting/gatk/iterators/LocusIteratorByState.java b/java/src/org/broadinstitute/sting/gatk/iterators/LocusIteratorByState.java
index 7f71303f2..ad53372f3 100755
--- a/java/src/org/broadinstitute/sting/gatk/iterators/LocusIteratorByState.java
+++ b/java/src/org/broadinstitute/sting/gatk/iterators/LocusIteratorByState.java
@@ -40,8 +40,8 @@ import java.util.*;
 
 /** Iterator that traverses a SAM File, accumulating information on a per-locus basis */
 public class LocusIteratorByState extends LocusIterator {
-    private static long discarded_bases = 0L;
-    private static long observed_bases = 0L;
+//    private static long discarded_bases = 0L;
+//    private static long observed_bases = 0L;
 
     //
     // todo -- eric, add your UG filters here
@@ -69,7 +69,7 @@ public class LocusIteratorByState extends LocusIterator {
     private final Collection<String> sampleNames = new ArrayList<String>();
     private final ReadStateManager readStates;
 
-    private class SAMRecordState {
+    static private class SAMRecordState {
         SAMRecord read;
         int readOffset = -1;     // how far are we offset from the start of the read bases?
         int genomeOffset = -1;   // how far are we offset from the alignment start on the genome?
@@ -226,7 +226,11 @@ public class LocusIteratorByState extends LocusIterator {
                             insertedBases = null;
 //                            System.out.println("Deleted "+eventLength +" bases after "+readOffset);
                         }
-                    } // continue onto the 'N' case !
+                    }
+                    // should be the same as N case
+                    genomeOffset++;
+                    done = true;
+                    break;
                 case N : // reference skip (looks and gets processed just like a "deletion", just different logical meaning)
                     genomeOffset++;
                     done = true;
@@ -448,11 +452,11 @@ public class LocusIteratorByState extends LocusIterator {
                         SAMRecordState state = iterator.next();
                         if ( state.getCurrentCigarOperator() != CigarOperator.D && state.getCurrentCigarOperator() != CigarOperator.N ) {
                             if ( filterRead(state.getRead(), location.getStart(), filters ) ) {
-                                discarded_bases++;
+                                //discarded_bases++;
                                 //printStatus("Adaptor bases", discarded_adaptor_bases);
                                 continue;
                             } else {
-                                observed_bases++;
+                                //observed_bases++;
                                 pile.add(new PileupElement(state.getRead(), state.getReadOffset()));
                                 size++;
                             }
@@ -504,10 +508,10 @@ public class LocusIteratorByState extends LocusIterator {
         return false;
     }
 
-    private void printStatus(final String title, long n) {
-        if ( n % 10000 == 0 )
-            System.out.printf("%s %d / %d = %.2f%n", title, n, observed_bases, 100.0 * n / (observed_bases + 1));
-    }
+//    private void printStatus(final String title, long n) {
+//        if ( n % 10000 == 0 )
+//            System.out.printf("%s %d / %d = %.2f%n", title, n, observed_bases, 100.0 * n / (observed_bases + 1));
+//    }
 
     private void updateReadStates() {
         for(String sampleName: sampleNames) {
@@ -865,7 +869,7 @@ public class LocusIteratorByState extends LocusIterator {
     /**
      * Note: assuming that, whenever we downsample, we downsample to an integer capacity.
      */
-    private class Counter {
+    static private class Counter {
         private int count;
 
         public Counter(int count) {
diff --git a/java/src/org/broadinstitute/sting/gatk/iterators/ReadFormattingIterator.java b/java/src/org/broadinstitute/sting/gatk/iterators/ReadFormattingIterator.java
index 18c4dc3f7..3a08e0677 100644
--- a/java/src/org/broadinstitute/sting/gatk/iterators/ReadFormattingIterator.java
+++ b/java/src/org/broadinstitute/sting/gatk/iterators/ReadFormattingIterator.java
@@ -20,7 +20,7 @@ public class ReadFormattingIterator implements StingSAMIterator {
     /**
      * Logger.
      */
-    protected static Logger logger = Logger.getLogger(ReadFormattingIterator.class);    
+    final protected static Logger logger = Logger.getLogger(ReadFormattingIterator.class);    
 
     /**
      * Iterator to which to pass
diff --git a/java/src/org/broadinstitute/sting/gatk/iterators/VerifyingSamIterator.java b/java/src/org/broadinstitute/sting/gatk/iterators/VerifyingSamIterator.java
index af143fa32..42a12b910 100644
--- a/java/src/org/broadinstitute/sting/gatk/iterators/VerifyingSamIterator.java
+++ b/java/src/org/broadinstitute/sting/gatk/iterators/VerifyingSamIterator.java
@@ -19,7 +19,6 @@ public class VerifyingSamIterator implements StingSAMIterator {
     StingSAMIterator it;
     SAMRecord last = null;
     boolean checkOrderP = true;
-    long nOutOfOrderReads = 0; 
 
     public VerifyingSamIterator(StingSAMIterator it) {
         this.it = it;
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/ClipReadsWalker.java b/java/src/org/broadinstitute/sting/gatk/walkers/ClipReadsWalker.java
index 7e5ad30bd..83e363b20 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/ClipReadsWalker.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/ClipReadsWalker.java
@@ -36,6 +36,7 @@ import org.broadinstitute.sting.utils.collections.Pair;
 import org.broadinstitute.sting.gatk.io.StingSAMFileWriter;
 import org.broadinstitute.sting.gatk.contexts.ReferenceContext;
 
+import java.nio.channels.IllegalSelectorException;
 import java.util.*;
 import java.util.regex.Pattern;
 import java.util.regex.Matcher;
@@ -336,6 +337,8 @@ public class ClipReadsWalker extends ReadWalker<ClipReadsWalker.ReadClipper, Cli
                     case MATCHES_CLIP_SEQ:
                         data.incSeqClippedBases((String) op.extraInfo, op.getLength());
                         break;
+                    default:
+                        throw new IllegalStateException("Unexpected Clipping operator type " + op);
                 }
             }
         }
@@ -353,7 +356,7 @@ public class ClipReadsWalker extends ReadWalker<ClipReadsWalker.ReadClipper, Cli
     //
     // --------------------------------------------------------------------------------------------------------------
 
-    private class SeqToClip {
+    private static class SeqToClip {
         String name;
         String seq, revSeq;
         Pattern fwdPat, revPat;
@@ -475,6 +478,8 @@ public class ClipReadsWalker extends ReadWalker<ClipReadsWalker.ReadClipper, Cli
 
                     break;
                     //throw new RuntimeException("Softclipping of bases not yet implemented.");
+                default:
+                    throw new IllegalStateException("Unexpected Clipping operator type " + algorithm);
             }
         }
     }
@@ -492,7 +497,7 @@ public class ClipReadsWalker extends ReadWalker<ClipReadsWalker.ReadClipper, Cli
     /**
      * A simple collection of the clipping operations to apply to a read along with its read
      */
-    public class ReadClipper {
+    static public class ReadClipper {
         SAMRecord read;
         List<ClippingOp> ops = null;
 
@@ -551,7 +556,7 @@ public class ClipReadsWalker extends ReadWalker<ClipReadsWalker.ReadClipper, Cli
         }
     }
 
-    public class ClippingData {
+    public static class ClippingData {
         public long nTotalReads = 0;
         public long nTotalBases = 0;
         public long nClippedReads = 0;
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/FlagStatWalker.java b/java/src/org/broadinstitute/sting/gatk/walkers/FlagStatWalker.java
index 87ce1f93e..27298c4ed 100644
--- a/java/src/org/broadinstitute/sting/gatk/walkers/FlagStatWalker.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/FlagStatWalker.java
@@ -42,7 +42,7 @@ import java.text.NumberFormat;
 @Requires({DataSource.READS})
 public class FlagStatWalker extends ReadWalker<Integer, Integer> {
     // what comes out of the flagstat
-    class FlagStat {
+    static class FlagStat {
         int readCount = 0;
         int QC_failure = 0;
         int duplicates = 0;
@@ -144,7 +144,7 @@ public class FlagStatWalker extends ReadWalker<Integer, Integer> {
                 myStat.singletons++;
             }
         }
-        if (read.getReferenceIndex() >= 0 && read.getMateReferenceIndex() >= 0 && read.getReferenceIndex() != read.getMateReferenceIndex()) {
+        if (read.getReferenceIndex() >= 0 && read.getMateReferenceIndex() >= 0 && ! read.getReferenceIndex().equals(read.getMateReferenceIndex())) {
             myStat.with_mate_mapped_to_a_different_chr++;
 
             if (read.getMappingQuality() >= 5) {
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/Walker.java b/java/src/org/broadinstitute/sting/gatk/walkers/Walker.java
index 9c9b07c20..b5dc3b868 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/Walker.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/Walker.java
@@ -43,7 +43,7 @@ import net.sf.picard.filter.SamRecordFilter;
  * To change this template use File | Settings | File Templates.
  */
 public abstract class Walker<MapType, ReduceType> {
-    protected static Logger logger = Logger.getLogger(Walker.class);
+    final protected static Logger logger = Logger.getLogger(Walker.class);
 
     /**
      * A stream for writing normal (non-error) output.  System.out by default.
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/coverage/CallableLociWalker.java b/java/src/org/broadinstitute/sting/gatk/walkers/coverage/CallableLociWalker.java
index f663a2bb7..651cdd381 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/coverage/CallableLociWalker.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/coverage/CallableLociWalker.java
@@ -91,7 +91,7 @@ public class CallableLociWalker extends LocusWalker<CallableLociWalker.CallableB
         }
     }
 
-    public class Integrator {
+    public static class Integrator {
         long counts[] = new long[CalledState.values().length];
         CallableBaseState state = null;
     }
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/coverage/DepthOfCoverageWalker.java b/java/src/org/broadinstitute/sting/gatk/walkers/coverage/DepthOfCoverageWalker.java
index 78398a30f..cce9edc64 100644
--- a/java/src/org/broadinstitute/sting/gatk/walkers/coverage/DepthOfCoverageWalker.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/coverage/DepthOfCoverageWalker.java
@@ -138,8 +138,7 @@ public class DepthOfCoverageWalker extends LocusWalker<Map<CoverageAggregator.Ag
         }
 
         if ( ! goodOutputFormat ) {
-            System.out.println("Improper output format. Can be one of table,rtable,csv. Was "+outputFormat);
-            System.exit(0);
+            throw new IllegalArgumentException("Improper output format. Can be one of table,rtable,csv. Was "+outputFormat);
         }
 
         if ( outputFormat.equals("csv") ) {
@@ -604,10 +603,11 @@ public class DepthOfCoverageWalker extends LocusWalker<Map<CoverageAggregator.Ag
         hBuilder.append(String.format("from_%d_to_inf%n",leftEnds[leftEnds.length-1]));
         output.print(hBuilder.toString());
         Map<String,int[]> histograms = stats.getHistograms();
-        for ( String s : histograms.keySet() ) {
+
+        for ( Map.Entry<String, int[]> p : histograms.entrySet() ) {
             StringBuilder sBuilder = new StringBuilder();
-            sBuilder.append(String.format("sample_%s",s));
-            for ( int count : histograms.get(s) ) {
+            sBuilder.append(String.format("sample_%s",p.getKey()));
+            for ( int count : p.getValue() ) {
                 sBuilder.append(String.format("%s%d",separator,count));
             }
             sBuilder.append(String.format("%n"));
@@ -698,8 +698,9 @@ public class DepthOfCoverageWalker extends LocusWalker<Map<CoverageAggregator.Ag
         Map<String,Long> totals = stats.getTotals();
         int[] leftEnds = stats.getEndpoints();
 
-        for ( String s : histograms.keySet() ) {
-            int[] histogram = histograms.get(s);
+        for ( Map.Entry<String, int[]> p : histograms.entrySet() ) {
+            String s = p.getKey();
+            int[] histogram = p.getValue();
             int median = getQuantile(histogram,0.5);
             int q1 = getQuantile(histogram,0.25);
             int q3 = getQuantile(histogram,0.75);
@@ -821,6 +822,8 @@ public class DepthOfCoverageWalker extends LocusWalker<Map<CoverageAggregator.Ag
         for (CoverageAggregator.AggregationType t : aggregationTypes ) {
             List<String> order = orderCheck.get(t);
             List<String> namesInAg = ag.getIdentifiersByType().get(t);
+
+            // todo -- chris check me
             Set<String> namesInDOCS = ag.getCoverageByAggregationType(t).getAllSamples();
             int index = 0;
             for ( String s : namesInAg ) {
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/fasta/FastaReferenceWalker.java b/java/src/org/broadinstitute/sting/gatk/walkers/fasta/FastaReferenceWalker.java
index 9243a99c2..ad0a0e4b2 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/fasta/FastaReferenceWalker.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/fasta/FastaReferenceWalker.java
@@ -66,19 +66,19 @@ public class FastaReferenceWalker extends RefWalker<Pair<GenomeLoc, String>, Gen
         // if there is no interval to the left, then this is the first one
         if ( sum == null ) {
             sum = value.first;
-            fasta.append(value.second.toString());
+            fasta.append(value.second);
         }
         // if the intervals don't overlap, print out the leftmost one and start a new one
         // (end of contig or new interval)
         else if ( value.first.getStart() != sum.getStop() + 1 ) {
             fasta.flush();
             sum = value.first;
-            fasta.append(value.second.toString());
+            fasta.append(value.second);
         }
         // otherwise, merge them
         else {
             sum = GenomeLocParser.setStop(sum, value.first.getStop());
-            fasta.append(value.second.toString());
+            fasta.append(value.second);
         }
 		return sum;
 	}
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/CycleCovariate.java b/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/CycleCovariate.java
index 760f4b897..5e0a49cca 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/CycleCovariate.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/CycleCovariate.java
@@ -45,16 +45,12 @@ import org.broadinstitute.sting.utils.Utils;
  */
 
 public class CycleCovariate implements StandardCovariate {
-
-    private static boolean warnedUserBadPlatform = false;
-    private static String defaultPlatform = null;
-
     // Initialize any member variables using the command-line arguments passed to the walkers
     public void initialize( final RecalibrationArgumentCollection RAC ) {
         if( RAC.DEFAULT_PLATFORM != null ) {
             if( RAC.DEFAULT_PLATFORM.equalsIgnoreCase( "SLX" ) || RAC.DEFAULT_PLATFORM.equalsIgnoreCase( "ILLUMINA" ) ||
                 RAC.DEFAULT_PLATFORM.contains( "454" ) || RAC.DEFAULT_PLATFORM.equalsIgnoreCase( "SOLID" ) || RAC.DEFAULT_PLATFORM.equalsIgnoreCase( "ABI_SOLID" ) ) {
-                defaultPlatform = RAC.DEFAULT_PLATFORM;
+                // nothing to do
             } else {
                 throw new StingException( "The requested default platform (" + RAC.DEFAULT_PLATFORM +") is not a recognized platform. Implemented options are illumina, 454, and solid");
             }
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/RecalDataManager.java b/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/RecalDataManager.java
index 04650cea5..66e8cc4d1 100644
--- a/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/RecalDataManager.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/recalibration/RecalDataManager.java
@@ -168,7 +168,7 @@ public class RecalDataManager {
     }
 
     private void checkForSingletons( final Map data ) {
-
+        // todo -- this looks like it's better just as a data.valueSet() call?
         for( Object comp : data.keySet() ) {
             final Object val = data.get(comp);
             if( val instanceof RecalDatum ) { // We are at the end of the nested hash maps
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/CountVariants.java b/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/CountVariants.java
index f101050ce..e9654cda4 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/CountVariants.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/CountVariants.java
@@ -111,6 +111,8 @@ public class CountVariants extends VariantEvaluator {
             case MIXED:
                 nComplex++;
                 break;
+            default:
+                throw new StingException("Unexpected VariantContext type " + vc1.getType());
         }
 
         for (Genotype g : vc1.getGenotypes().values()) {
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/GenotypeConcordance.java b/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/GenotypeConcordance.java
index 5d0dbace6..75237ba16 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/GenotypeConcordance.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/GenotypeConcordance.java
@@ -59,7 +59,7 @@ public class GenotypeConcordance extends VariantEvaluator {
     private static final int MAX_MISSED_VALIDATION_DATA = 100;
 
 
-    class FrequencyStats implements TableType {
+    static class FrequencyStats implements TableType {
         class Stats {
             public Stats(int found, int missed) { nFound = found; nMissed = missed; }
             public long nFound = 0;
@@ -103,8 +103,8 @@ public class GenotypeConcordance extends VariantEvaluator {
         }
     }
 
-    class QualityScoreHistograms implements TableType {
-        final int NUM_BINS = 20;
+    static class QualityScoreHistograms implements TableType {
+        final static int NUM_BINS = 20;
         final HashMap<Integer,Integer> truePositiveQualityScoreMap = new HashMap<Integer,Integer>(); // A HashMap holds all the quality scores until we are able to bin them appropriately
         final HashMap<Integer,Integer> falsePositiveQualityScoreMap = new HashMap<Integer,Integer>();
         final int truePositiveHist[] = new int[NUM_BINS]; // the final histograms that get reported out
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/IndelLengthHistogram.java b/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/IndelLengthHistogram.java
index ac345ed48..f264bfaaa 100644
--- a/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/IndelLengthHistogram.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/varianteval/IndelLengthHistogram.java
@@ -17,7 +17,7 @@ import org.broadinstitute.sting.utils.StingException;
  */
 @Analysis(name = "Indel length histograms", description = "Shows the distrbution of insertion/deletion event lengths (negative for deletion, positive for insertion)")
 public class IndelLengthHistogram extends VariantEvaluator {
-    private final int SIZE_LIMIT = 50;
+    private static final int SIZE_LIMIT = 50;
     @DataPoint(name="indelLengthHistogram",description="Histogram of indel lengths")
     IndelHistogram indelHistogram = new IndelHistogram(SIZE_LIMIT);
 
@@ -25,7 +25,7 @@ public class IndelLengthHistogram extends VariantEvaluator {
      * Indel length histogram table object
      */
 
-    class IndelHistogram implements TableType {
+    static class IndelHistogram implements TableType {
         private Integer[] colKeys;
         private int limit;
         private String[] rowKeys = {"EventLength"};
diff --git a/java/src/org/broadinstitute/sting/gatk/walkers/variantutils/CombineVariants.java b/java/src/org/broadinstitute/sting/gatk/walkers/variantutils/CombineVariants.java
index d9df07dd0..44e1dce93 100755
--- a/java/src/org/broadinstitute/sting/gatk/walkers/variantutils/CombineVariants.java
+++ b/java/src/org/broadinstitute/sting/gatk/walkers/variantutils/CombineVariants.java
@@ -91,7 +91,7 @@ public class CombineVariants extends RodWalker<Integer, Integer> {
         if ( rodNames.size() != priority.size() )
             throw new StingException("The priority list must contain exactly one rod binding per ROD provided to the GATK: rodNames=" + rodNames + " priority=" + priority);
 
-        if ( ! rodNames.containsAll(rodNames) )
+        if ( ! rodNames.containsAll(priority) )
             throw new StingException("Not all priority elements provided as input RODs: " + PRIORITY_STRING);
     }
 
diff --git a/java/src/org/broadinstitute/sting/playground/gatk/walkers/LocusMismatchWalker.java b/java/src/org/broadinstitute/sting/playground/gatk/walkers/LocusMismatchWalker.java
index 0f32669a5..52938691c 100755
--- a/java/src/org/broadinstitute/sting/playground/gatk/walkers/LocusMismatchWalker.java
+++ b/java/src/org/broadinstitute/sting/playground/gatk/walkers/LocusMismatchWalker.java
@@ -133,14 +133,15 @@ public class LocusMismatchWalker extends LocusWalker<String,Integer> implements
         }
 
         if ( nMismatches < maxNumMismatches && nMismatches >= minMismatches && usableDepth >= minDepth ) {
-            String baseCountString = "";
+            StringBuffer baseCountString = new StringBuffer();
             for ( byte b : BaseUtils.BASES ) {
-                baseCountString += baseCounts[BaseUtils.simpleBaseToBaseIndex(b)] + " ";
+                baseCountString.append(baseCounts[BaseUtils.simpleBaseToBaseIndex(b)]);
+                baseCountString.append(" ");
             }
             return String.format("%s %c %10s %5.2f %d %d %d %s",
                     pileup.getLocation(), ref.getBaseAsChar(),
                     getGenotypeClass(g), 10 * g.getNegLog10PError(),
-                    usableDepth, nMismatches, qSumMismatches, baseCountString);
+                    usableDepth, nMismatches, qSumMismatches, baseCountString.toString());
         }
 
         return null;
diff --git a/java/src/org/broadinstitute/sting/playground/gatk/walkers/hybridselection/HybSelPerformanceWalker.java b/java/src/org/broadinstitute/sting/playground/gatk/walkers/hybridselection/HybSelPerformanceWalker.java
index 2758df86e..5335aa88d 100755
--- a/java/src/org/broadinstitute/sting/playground/gatk/walkers/hybridselection/HybSelPerformanceWalker.java
+++ b/java/src/org/broadinstitute/sting/playground/gatk/walkers/hybridselection/HybSelPerformanceWalker.java
@@ -230,7 +230,7 @@ public class HybSelPerformanceWalker extends LocusWalker<Integer, HybSelPerforma
                 basesConsidered += length;
             }
         }
-        double meanTargetCoverage = totalCoverage / basesConsidered;
+        double meanTargetCoverage = (1.0*totalCoverage) / basesConsidered;
 
 
         for(Pair<GenomeLoc, TargetInfo> pair : results) {