diff --git a/com.ibm.wala.core.tests/src/com/ibm/wala/core/tests/cha/SourceMapTest.java b/com.ibm.wala.core.tests/src/com/ibm/wala/core/tests/cha/SourceMapTest.java
index 2008e698a..cfc37eb82 100644
--- a/com.ibm.wala.core.tests/src/com/ibm/wala/core/tests/cha/SourceMapTest.java
+++ b/com.ibm.wala.core.tests/src/com/ibm/wala/core/tests/cha/SourceMapTest.java
@@ -10,6 +10,8 @@
  *******************************************************************************/
 package com.ibm.wala.core.tests.cha;
 
+import java.io.IOException;
+
 import com.ibm.wala.classLoader.IClass;
 import com.ibm.wala.core.tests.util.TestConstants;
 import com.ibm.wala.core.tests.util.WalaTestCase;
@@ -29,7 +31,7 @@ public class SourceMapTest extends WalaTestCase {
 
   private final static String CLASS_IN_PRIMORDIAL_JAR = "Lcom/ibm/wala/model/SyntheticFactory";
 
-  public void testHello() throws ClassHierarchyException {
+  public void testHello() throws ClassHierarchyException, IOException {
     AnalysisScope scope = null;
     scope = AnalysisScopeReader.readJavaScope(TestConstants.HELLO, null, MY_CLASSLOADER);
     // TODO: it's annoying to have to build a class hierarchy here.
@@ -43,7 +45,7 @@ public class SourceMapTest extends WalaTestCase {
     assertTrue(sourceFile != null);
   }
 
-  public void testFromJar() throws ClassHierarchyException {
+  public void testFromJar() throws ClassHierarchyException, IOException {
     AnalysisScope scope = null;
     scope = AnalysisScopeReader.readJavaScope(TestConstants.HELLO, null, MY_CLASSLOADER);
     // TODO: it's annoying to have to build a class hierarchy here.
diff --git a/com.ibm.wala.core.tests/src/com/ibm/wala/demandpa/driver/CompareToZeroOneCFADriver.java b/com.ibm.wala.core.tests/src/com/ibm/wala/demandpa/driver/CompareToZeroOneCFADriver.java
index ce41ed3a7..96cfdb0ab 100644
--- a/com.ibm.wala.core.tests/src/com/ibm/wala/demandpa/driver/CompareToZeroOneCFADriver.java
+++ b/com.ibm.wala.core.tests/src/com/ibm/wala/demandpa/driver/CompareToZeroOneCFADriver.java
@@ -118,7 +118,7 @@ public class CompareToZeroOneCFADriver {
   }
 
   @SuppressWarnings("unused")
-  private static void runApplication(String appJar) throws IllegalArgumentException, CancelException {
+  private static void runApplication(String appJar) throws IllegalArgumentException, CancelException, IOException {
     Trace.println("=======---------------=============");
     Trace.println("ANALYZING " + appJar + "\n\n");
 
diff --git a/com.ibm.wala.core.tests/src/com/ibm/wala/examples/drivers/GVCallGraph.java b/com.ibm.wala.core.tests/src/com/ibm/wala/examples/drivers/GVCallGraph.java
index 3892e7432..bcd218f2a 100644
--- a/com.ibm.wala.core.tests/src/com/ibm/wala/examples/drivers/GVCallGraph.java
+++ b/com.ibm.wala.core.tests/src/com/ibm/wala/examples/drivers/GVCallGraph.java
@@ -40,8 +40,7 @@ import com.ibm.wala.viz.DotUtil;
 import com.ibm.wala.viz.GVUtil;
 
 /**
- * This simple example WALA application builds a call graph and fires off
- * ghostview to visualize a DOT representation.
+ * This simple example WALA application builds a call graph and fires off ghostview to visualize a DOT representation.
  * 
  * @author sfink
  */
@@ -50,8 +49,7 @@ public class GVCallGraph {
   private final static String PS_FILE = "cg.ps";
 
   /**
-   * Usage: args = "-appJar [jar file name] {-exclusionFile
-   * [exclusionFileName]}" The "jar file name" should be something like
+   * Usage: args = "-appJar [jar file name] {-exclusionFile [exclusionFileName]}" The "jar file name" should be something like
    * "c:/temp/testdata/java_cup.jar"
    * 
    * @throws CancelException
@@ -62,8 +60,7 @@ public class GVCallGraph {
   }
 
   /**
-   * Usage: args = "-appJar [jar file name] {-exclusionFile
-   * [exclusionFileName]}" The "jar file name" should be something like
+   * Usage: args = "-appJar [jar file name] {-exclusionFile [exclusionFileName]}" The "jar file name" should be something like
    * "c:/temp/testdata/java_cup.jar"
    * 
    * @throws CancelException
@@ -76,8 +73,7 @@ public class GVCallGraph {
   }
 
   /**
-   * @param appJar
-   *            something like "c:/temp/testdata/java_cup.jar"
+   * @param appJar something like "c:/temp/testdata/java_cup.jar"
    * @throws CancelException
    * @throws IllegalArgumentException
    */
@@ -111,16 +107,16 @@ public class GVCallGraph {
   }
 
   /**
-   * @param appJar
-   *            something like "c:/temp/testdata/java_cup.jar"
+   * @param appJar something like "c:/temp/testdata/java_cup.jar"
    * @return a call graph
    * @throws CancelException
    * @throws IllegalArgumentException
+   * @throws IOException 
    */
   public static Graph<CGNode> buildPrunedCallGraph(String appJar, File exclusionFile) throws WalaException,
-      IllegalArgumentException, CancelException {
-    AnalysisScope scope = AnalysisScopeReader.makeJavaBinaryAnalysisScope(appJar, exclusionFile != null ? exclusionFile
-        : new File(CallGraphTestUtil.REGRESSION_EXCLUSIONS));
+      IllegalArgumentException, CancelException, IOException {
+    AnalysisScope scope = AnalysisScopeReader.makeJavaBinaryAnalysisScope(appJar, exclusionFile != null ? exclusionFile : new File(
+        CallGraphTestUtil.REGRESSION_EXCLUSIONS));
 
     ClassHierarchy cha = ClassHierarchy.make(scope);
 
@@ -132,11 +128,11 @@ public class GVCallGraph {
     // //
     com.ibm.wala.ipa.callgraph.CallGraphBuilder builder = Util.makeZeroCFABuilder(options, new AnalysisCache(), cha, scope);
     CallGraph cg = builder.makeCallGraph(options, null);
-    
+
     System.err.println(CallGraphStats.getStats(cg));
 
     Graph<CGNode> g = pruneForAppLoader(cg);
-    
+
     return g;
   }
 
@@ -149,11 +145,10 @@ public class GVCallGraph {
    * 
    * Usage:
    * <ul>
-   * <li> args[0] : "-appJar"
+   * <li>args[0] : "-appJar"
    * <li> args[1] : something like "c:/temp/testdata/java_cup.jar" </ul?
    * 
-   * @throws UnsupportedOperationException
-   *             if command-line is malformed.
+   * @throws UnsupportedOperationException if command-line is malformed.
    */
   public static void validateCommandLine(Properties p) {
     if (p.get("appJar") == null) {
diff --git a/com.ibm.wala.core/src/com/ibm/wala/eclipse/AbstractJavaAnalysisAction.java b/com.ibm.wala.core/src/com/ibm/wala/eclipse/AbstractJavaAnalysisAction.java
index 43040f798..c83fe4c2c 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/eclipse/AbstractJavaAnalysisAction.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/eclipse/AbstractJavaAnalysisAction.java
@@ -107,8 +107,9 @@ public abstract class AbstractJavaAnalysisAction implements IObjectActionDelegat
 
   /**
    * create an analysis scope as the union of a bunch of EclipseProjectPath
+   * @throws IOException 
    */
-  private static AnalysisScope mergeProjectPaths(Collection<EclipseProjectPath> projectPaths) {
+  private static AnalysisScope mergeProjectPaths(Collection<EclipseProjectPath> projectPaths) throws IOException {
     AnalysisScope scope = AnalysisScope.createJavaAnalysisScope();
 
     Collection<Module> seen = HashSetFactory.make();
@@ -121,7 +122,7 @@ public abstract class AbstractJavaAnalysisAction implements IObjectActionDelegat
   }
 
   private static void buildScope(ClassLoaderReference loader, Collection<EclipseProjectPath> projectPaths, AnalysisScope scope,
-      Collection<Module> seen) {
+      Collection<Module> seen) throws IOException {
     for (EclipseProjectPath path : projectPaths) {
       AnalysisScope pScope = path.toAnalysisScope((File) null);
       for (Module m : pScope.getModules(loader)) {
diff --git a/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/EclipseProjectPath.java b/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/EclipseProjectPath.java
index d2dc743e2..21e5afea3 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/EclipseProjectPath.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/EclipseProjectPath.java
@@ -299,8 +299,10 @@ public class EclipseProjectPath {
 
   /**
    * Convert this path to a WALA analysis scope
+   * 
+   * @throws IOException
    */
-  public AnalysisScope toAnalysisScope(ClassLoader classLoader, File exclusionsFile) {
+  public AnalysisScope toAnalysisScope(ClassLoader classLoader, File exclusionsFile) throws IOException {
     AnalysisScope scope = AnalysisScopeReader.readJavaScope(AbstractAnalysisEngine.SYNTHETIC_J2SE_MODEL, exclusionsFile,
         classLoader);
     return toAnalysisScope(scope);
@@ -338,11 +340,11 @@ public class EclipseProjectPath {
     }
   }
 
-  public AnalysisScope toAnalysisScope(final File exclusionsFile) {
+  public AnalysisScope toAnalysisScope(final File exclusionsFile) throws IOException {
     return toAnalysisScope(getClass().getClassLoader(), exclusionsFile);
   }
 
-  public AnalysisScope toAnalysisScope() {
+  public AnalysisScope toAnalysisScope() throws IOException {
     return toAnalysisScope(getClass().getClassLoader(), null);
   }
 
@@ -352,7 +354,12 @@ public class EclipseProjectPath {
 
   @Override
   public String toString() {
-    return toAnalysisScope((File) null).toString();
+    try {
+      return toAnalysisScope((File) null).toString();
+    } catch (IOException e) {
+      e.printStackTrace();
+      return "Error in toString()";
+    }
   }
 
   private IPluginModelBase findModel(IProject p) {
diff --git a/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/JdtUtil.java b/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/JdtUtil.java
index a21eb53a7..df98a9ddd 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/JdtUtil.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/eclipse/util/JdtUtil.java
@@ -104,20 +104,6 @@ public class JdtUtil {
     return className;
   }
 
-  // public static String getMethodSignature(IMethod method) {
-  // if (method == null) {
-  // throw new IllegalArgumentException("method is null");
-  // }
-  // try {
-  // String methodParamReturnInfo = method.getSignature();
-  // String methodName = method.getElementName();
-  // String methodSignature = methodName + " " + methodParamReturnInfo;
-  // return methodSignature;
-  // } catch (JavaModelException e) {
-  // }
-  // return "";
-  // }
-
   /**
    * Return a unique string representing the specified Java element across projects in the workspace. The returned string can be
    * used as a handle to create JavaElement by 'JavaCore.create(String)'
@@ -135,6 +121,7 @@ public class JdtUtil {
     return javaElt.getHandleIdentifier();
   }
 
+  @Deprecated
   public static IJavaElement createJavaElementFromJdtHandle(String jdtHandle) {
     return JavaCore.create(jdtHandle);
   }
diff --git a/com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/propagation/PointsToMap.java b/com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/propagation/PointsToMap.java
index a63d90dc0..561d8912d 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/propagation/PointsToMap.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/propagation/PointsToMap.java
@@ -84,6 +84,9 @@ public class PointsToMap {
    * If p is unified, returns the representative for p.
    */
   public PointsToSetVariable getPointsToSet(PointerKey p) {
+    if (p == null) {
+      throw new IllegalArgumentException("null p");
+    }
     if (isImplicit(p)) {
       throw new IllegalArgumentException("unexpected: shouldn't ask a PointsToMap for an implicit points-to-set: " + p);
     }
@@ -111,6 +114,9 @@ public class PointsToMap {
    * record that a particular points-to-set is represented implicitly
    */
   public void recordImplicit(PointerKey key) {
+    if (key == null) {
+      throw new IllegalArgumentException("null key");
+    }
     int i = findOrCreateIndex(key);
     pointsToSets.set(i, IMPLICIT);
   }
diff --git a/com.ibm.wala.core/src/com/ibm/wala/model/SyntheticFactory.java b/com.ibm.wala.core/src/com/ibm/wala/model/SyntheticFactory.java
index ded3ddd53..a1317239a 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/model/SyntheticFactory.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/model/SyntheticFactory.java
@@ -11,10 +11,7 @@
 package com.ibm.wala.model;
 
 /**
- * 
  * A bogus class to support returning "unknown" objects
- * 
- * @author sfink
  */
 public class SyntheticFactory {
 
diff --git a/com.ibm.wala.core/src/com/ibm/wala/util/config/AnalysisScopeReader.java b/com.ibm.wala.core/src/com/ibm/wala/util/config/AnalysisScopeReader.java
index 9bd43f80c..57093bb46 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/util/config/AnalysisScopeReader.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/util/config/AnalysisScopeReader.java
@@ -32,29 +32,29 @@ import com.ibm.wala.util.strings.Atom;
 
 /**
  * Reads {@link AnalysisScope} from a text file.
- * 
  */
 public class AnalysisScopeReader {
 
   private static final ClassLoader MY_CLASSLOADER = AnalysisScopeReader.class.getClassLoader();
 
   private static final String BASIC_FILE = "primordial.txt";
-  
-  public static AnalysisScope readJavaScope(String scopeFileName, File exclusionsFile, ClassLoader javaLoader) {
-    AnalysisScope scope = AnalysisScope.createJavaAnalysisScope();
 
+  public static AnalysisScope readJavaScope(String scopeFileName, File exclusionsFile, ClassLoader javaLoader) throws IOException {
+    AnalysisScope scope = AnalysisScope.createJavaAnalysisScope();
     return read(scope, scopeFileName, exclusionsFile, javaLoader, CorePlugin.getDefault());
   }
-  
-  private static AnalysisScope readJavaScope(String scopeFileName, File exclusionsFile, ClassLoader javaLoader, Plugin plugIn) {
+
+  private static AnalysisScope readJavaScope(String scopeFileName, File exclusionsFile, ClassLoader javaLoader, Plugin plugIn) throws IOException {
     AnalysisScope scope = AnalysisScope.createJavaAnalysisScope();
     return read(scope, scopeFileName, exclusionsFile, javaLoader, plugIn);
   }
 
-  private static AnalysisScope read(AnalysisScope scope, String scopeFileName, File exclusionsFile, ClassLoader javaLoader, Plugin plugIn) {
+  private static AnalysisScope read(AnalysisScope scope, String scopeFileName, File exclusionsFile, ClassLoader javaLoader,
+      Plugin plugIn) throws IOException {
     BufferedReader r = null;
     try {
-      File scopeFile = (plugIn == null) ? FileProvider.getFile(scopeFileName, javaLoader): FileProvider.getFileFromPlugin(plugIn, scopeFileName);
+      File scopeFile = (plugIn == null) ? FileProvider.getFile(scopeFileName, javaLoader) : FileProvider.getFileFromPlugin(plugIn,
+          scopeFileName);
       assert scopeFile.exists();
 
       String line;
@@ -67,15 +67,12 @@ public class AnalysisScopeReader {
         scope.setExclusions(FileOfClasses.createFileOfClasses(exclusionsFile));
       }
 
-    } catch (IOException e) {
-      e.printStackTrace();
-      Assertions.UNREACHABLE(e.toString());
     } finally {
       if (r != null) {
         try {
           r.close();
         } catch (IOException e) {
-           e.printStackTrace();
+          e.printStackTrace();
         }
       }
     }
@@ -126,34 +123,37 @@ public class AnalysisScopeReader {
       Assertions.UNREACHABLE();
     }
   }
-  
+
   /**
-   * @param exclusionsFile file holding class hierarchy exclusions.  may be null
+   * @param exclusionsFile file holding class hierarchy exclusions. may be null
+   * @throws IOException 
    * @throws IllegalStateException if there are problmes reading wala properties
    */
-  public static AnalysisScope makePrimordialScope(File exclusionsFile) {
+  public static AnalysisScope makePrimordialScope(File exclusionsFile) throws IOException {
     return readJavaScope(BASIC_FILE, exclusionsFile, MY_CLASSLOADER, CorePlugin.getDefault());
   }
-  
-  private static AnalysisScope makePrimordialScope(File exclusionsFile, Plugin plugIn) {
+
+  private static AnalysisScope makePrimordialScope(File exclusionsFile, Plugin plugIn) throws IOException {
     return readJavaScope(BASIC_FILE, exclusionsFile, MY_CLASSLOADER, plugIn);
   }
 
   /**
    * @param classPath class path to analyze, delimited by File.pathSeparator
-   * @param exclusionsFile file holding class hierarchy exclusions.  may be null
+   * @param exclusionsFile file holding class hierarchy exclusions. may be null
+   * @throws IOException 
    * @throws IllegalStateException if there are problems reading wala properties
    */
-  public static AnalysisScope makeJavaBinaryAnalysisScope(String classPath, File exclusionsFile) {
+  public static AnalysisScope makeJavaBinaryAnalysisScope(String classPath, File exclusionsFile) throws IOException {
     return makeJavaBinaryAnalysisScope(classPath, exclusionsFile, CorePlugin.getDefault());
   }
-  
+
   /**
    * @param classPath class path to analyze, delimited by File.pathSeparator
-   * @param exclusionsFile file holding class hierarchy exclusions.  may be null
+   * @param exclusionsFile file holding class hierarchy exclusions. may be null
+   * @throws IOException 
    * @throws IllegalStateException if there are problems reading wala properties
    */
-  public static AnalysisScope makeJavaBinaryAnalysisScope(String classPath, File exclusionsFile, Plugin plugIn) {
+  public static AnalysisScope makeJavaBinaryAnalysisScope(String classPath, File exclusionsFile, Plugin plugIn) throws IOException {
     if (classPath == null) {
       throw new IllegalArgumentException("classPath null");
     }
diff --git a/com.ibm.wala.core/src/com/ibm/wala/util/intset/BasicNaturalRelation.java b/com.ibm.wala.core/src/com/ibm/wala/util/intset/BasicNaturalRelation.java
index 17ffd86e3..967ede78c 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/util/intset/BasicNaturalRelation.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/util/intset/BasicNaturalRelation.java
@@ -19,13 +19,10 @@ import com.ibm.wala.util.debug.Assertions;
 import com.ibm.wala.util.debug.Trace;
 
 /**
- * 
  * A relation between non-negative integers
  * 
  * This implementation uses n IntVectors, to hold the first n y's associated with each x, and then 1 extra vector of SparseIntSet to
  * hold the remaining ys.
- * 
- * @author sfink
  */
 public final class BasicNaturalRelation implements IBinaryNaturalRelation {
 
@@ -126,18 +123,14 @@ public final class BasicNaturalRelation implements IBinaryNaturalRelation {
    * This is performance-critical, so the implementation looks a little ugly in order to help out the compiler with redundancy
    * elimination.
    * 
-   * @param x
-   * @param y
    * @return true iff the relation changes as a result of this call.
    */
   public boolean add(int x, int y) throws IllegalArgumentException {
-    if (Assertions.verifyAssertions) {
-      if (x < 0) {
-        throw new IllegalArgumentException("illegal x: " + x);
-      }
-      if (y < 0) {
-        throw new IllegalArgumentException("illegal y: " + y);
-      }
+    if (x < 0) {
+      throw new IllegalArgumentException("illegal x: " + x);
+    }
+    if (y < 0) {
+      throw new IllegalArgumentException("illegal y: " + y);
     }
     maxX = Math.max(maxX, x);
     MutableIntSet delegated = (MutableIntSet) delegateStore.get(x);
@@ -351,6 +344,12 @@ public final class BasicNaturalRelation implements IBinaryNaturalRelation {
   }
 
   public void remove(int x, int y) {
+    if (x < 0) {
+      throw new IllegalArgumentException("illegal x: " + x);
+    }
+    if (y < 0) {
+      throw new IllegalArgumentException("illegal y: " + y);
+    }
     if (usingDelegate(x)) {
       // TODO: switch representation back to small store?
       MutableIntSet s = (MutableIntSet) delegateStore.get(x);
diff --git a/com.ibm.wala.core/src/com/ibm/wala/util/intset/IBinaryNaturalRelation.java b/com.ibm.wala.core/src/com/ibm/wala/util/intset/IBinaryNaturalRelation.java
index dbe3db541..15a38e3df 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/util/intset/IBinaryNaturalRelation.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/util/intset/IBinaryNaturalRelation.java
@@ -14,50 +14,35 @@ import com.ibm.wala.util.debug.VerboseAction;
 
 /**
  * a relation R(x,y) where x >= 0
- * 
- * @author sfink
  */
 public interface IBinaryNaturalRelation extends VerboseAction, Iterable<IntPair> {
   /**
    * Add (x,y) to the relation
    * 
-   * @param x
-   * @param y
    * @return true iff the relation changes as a result of this call.
    */
   public abstract boolean add(int x, int y);
 
   /**
-   * @param x
    * @return IntSet of y s.t. R(x,y) or null if none.
    */
   public abstract IntSet getRelated(int x);
 
   /**
-   * @param x
    * @return number of y s.t. R(x,y)
    */
   public abstract int getRelatedCount(int x);
 
   /**
-   * @param x
    * @return true iff there exists pair (x,y) for some y
    */
   public abstract boolean anyRelated(int x);
   
-  /**
-   * @param x
-   * @param y
-   */
   public abstract void remove(int x, int y);
 
-  /**
-   */
   public abstract void removeAll(int x);
 
   /**
-   * @param x
-   * @param y
    * @return true iff (x,y) \in R
    */
   public abstract boolean contains(int x, int y);
diff --git a/com.ibm.wala.core/src/com/ibm/wala/util/intset/MultiModalIntVector.java b/com.ibm.wala.core/src/com/ibm/wala/util/intset/MultiModalIntVector.java
index 9640d0918..32915ec03 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/util/intset/MultiModalIntVector.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/util/intset/MultiModalIntVector.java
@@ -62,6 +62,9 @@ public class MultiModalIntVector implements IntVector {
   }
 
   public MultiModalIntVector(int defaultValue, int initialSize) {
+    if (initialSize <= 0) {
+      throw new IllegalArgumentException("invalid initialSize: " + initialSize);
+    }
     this.defaultValue = defaultValue;
     init(initialSize, defaultValue);
   }
@@ -94,8 +97,8 @@ public class MultiModalIntVector implements IntVector {
    * @see com.ibm.wala.util.intset.IntVector#get(int)
    */
   public int get(int x) {
-    if (Assertions.verifyAssertions) {
-      Assertions._assert(x >= 0);
+    if (x < 0) {
+      throw new IllegalArgumentException("illegal x: " + x);
     }
     int index = x;
     if (index < byteStore.length) {
@@ -120,8 +123,11 @@ public class MultiModalIntVector implements IntVector {
    * @see com.ibm.wala.util.intset.IntVector#set(int, int)
    */
   public void set(int x, int value) {
-    if (Assertions.verifyAssertions) {
-      Assertions._assert(x >= 0);
+    if (x < 0) {
+      throw new IllegalArgumentException("illegal x: " + x);
+    }
+    if (x > MAX_SIZE) {
+      throw new IllegalArgumentException("x is too big: " + x);
     }
     maxIndex = Math.max(maxIndex, x); // Find out if the new position is bigger than size of the array
     handleMorph(x, value);
@@ -241,42 +247,6 @@ public class MultiModalIntVector implements IntVector {
     }
   }
 
-  /*
-   * @see com.ibm.wala.util.intset.IntVector#reportStats()
-   */
-  public void performVerboseAction() {
-    int length = getStoreLength();
-    Trace.println("size:       " + length);
-    Trace.println("occupancy:  " + computeOccupancy(length));
-  }
-
-  /**
-   * @return the percentage of entries in delegateStore that are non-null
-   */
-  private double computeOccupancy(int length) {
-    int count1 = 0;
-    int internalLength = length;
-    for (int i = 0; i < internalLength && i < byteStore.length; i++) {
-      if (byteStore[i] != -1) {
-        count1++;
-      }
-    }
-    length -= byteStore.length;
-    for (int i = 0; i < internalLength && i < byteStore.length; i++) {
-      if (shortStore[i] != -1) {
-        count1++;
-      }
-    }
-    length -= shortStore.length;
-    for (int i = 0; i < internalLength && i < intStore.length; i++) {
-      if (intStore[i] != -1) {
-        count1++;
-      }
-    }
-    int count = count1;
-    return (double) count / (double) length;
-  }
-
   public int getMaxIndex() {
     return maxIndex;
   }
diff --git a/com.ibm.wala.core/src/com/ibm/wala/util/intset/MutableSharedBitVectorIntSet.java b/com.ibm.wala.core/src/com/ibm/wala/util/intset/MutableSharedBitVectorIntSet.java
index ec90072df..91d9290ec 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/util/intset/MutableSharedBitVectorIntSet.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/util/intset/MutableSharedBitVectorIntSet.java
@@ -469,6 +469,9 @@ public class MutableSharedBitVectorIntSet implements MutableIntSet {
    * @see com.ibm.wala.util.intset.IntSet#isSubset(com.ibm.wala.util.intset.IntSet)
    */
   public boolean isSubset(IntSet that) {
+    if (that == null) {
+      throw new IllegalArgumentException("null that");
+    }
     if (that instanceof MutableSharedBitVectorIntSet) {
       return isSubset((MutableSharedBitVectorIntSet) that);
     } else {
diff --git a/com.ibm.wala.core/src/com/ibm/wala/util/strings/StringStuff.java b/com.ibm.wala.core/src/com/ibm/wala/util/strings/StringStuff.java
index 875849012..d99f1abc7 100644
--- a/com.ibm.wala.core/src/com/ibm/wala/util/strings/StringStuff.java
+++ b/com.ibm.wala.core/src/com/ibm/wala/util/strings/StringStuff.java
@@ -350,11 +350,8 @@ public class StringStuff {
    * 
    * TODO: inefficient; needs tuning.
    * 
-   * @param name
-   * @param start
-   * @param length
    * @return an ImmutableByteArray that represents the package, or null if it's the unnamed package
-   * @throws IllegalArgumentException if name is null
+   * @throws IllegalArgumentException if name is null or malformed
    */
   public static ImmutableByteArray parseForClass(ImmutableByteArray name, int start, int length) throws IllegalArgumentException {
     if (name == null) {
@@ -363,6 +360,7 @@ public class StringStuff {
     if (name.length() == 0) {
       throw new IllegalArgumentException("invalid class name: zero length");
     }
+    try {
     if (parseForPackage(name, start, length) == null) {
       while (name.b[start] == '[') {
         start++;
@@ -383,6 +381,9 @@ public class StringStuff {
       int L = length - (lastSlash - start + 1);
       return new ImmutableByteArray(name.b, lastSlash + 1, L);
     }
+    } catch (ArrayIndexOutOfBoundsException e) {
+      throw new IllegalArgumentException("Malformed name: " + name + " " + start + " " + length);
+    }
   }
 
   /**