diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index dbe7c542..1ac07d71 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,3 +1,11 @@
+
+0.3.1
+=====
+- Fixed issue #17
+- Fixed NPE in DemoBoxStack-'x'
+- Added newArray(size) methods to DVector3 and DMatrix3
+
+
 0.3.0
 =====
 Migration to 0.13.1
diff --git a/core/src/main/java/org/ode4j/math/DMatrix3.java b/core/src/main/java/org/ode4j/math/DMatrix3.java
index 15862404..c047735d 100644
--- a/core/src/main/java/org/ode4j/math/DMatrix3.java
+++ b/core/src/main/java/org/ode4j/math/DMatrix3.java
@@ -967,4 +967,17 @@ public void getColumn1(DVector3 result) {
 	public void getColumn2(DVector3 result) {
 		result.set(get02(), get12(), get22());
 	}
+	
+	/**
+	 * Create an array of DVector instances.
+	 * @param size
+	 * @return AN array of DVector
+	 */
+	public final static DMatrix3[] newArray(int size) {
+		DMatrix3[] a = new DMatrix3[size];
+		for (int i = 0; i < size; i++) {
+			a[i] = new DMatrix3();
+		}
+		return a;
+	}
 }
diff --git a/core/src/main/java/org/ode4j/math/DVector3.java b/core/src/main/java/org/ode4j/math/DVector3.java
index 57d789a1..2ad4e6c8 100644
--- a/core/src/main/java/org/ode4j/math/DVector3.java
+++ b/core/src/main/java/org/ode4j/math/DVector3.java
@@ -701,6 +701,19 @@ public final void eqProd(DMatrix3C m, DVector3C v2) {
 	    set1( m.get10()*v2.get0()+  m.get11()*v2.get1()+  m.get12()*v2.get2() );
 	    set2( m.get20()*v2.get0()+  m.get21()*v2.get1()+  m.get22()*v2.get2() );
 	}
+	
+	/**
+	 * Create an array of DVector instances.
+	 * @param size
+	 * @return AN array of DVector
+	 */
+	public final static DVector3[] newArray(int size) {
+		DVector3[] a = new DVector3[size];
+		for (int i = 0; i < size; i++) {
+			a[i] = new DVector3();
+		}
+		return a;
+	}
 }
 
 
diff --git a/core/src/main/java/org/ode4j/ode/internal/CollideCylinderBox.java b/core/src/main/java/org/ode4j/ode/internal/CollideCylinderBox.java
index 188ae69e..02d8f90e 100644
--- a/core/src/main/java/org/ode4j/ode/internal/CollideCylinderBox.java
+++ b/core/src/main/java/org/ode4j/ode/internal/CollideCylinderBox.java
@@ -198,11 +198,10 @@ private void _cldInitCylinderBox()
 
 			// temp index
 			int i = 0;
-			DVector3[]	vTempBoxVertices = new DVector3[8];
+			DVector3[]	vTempBoxVertices = DVector3.newArray(8);
 			// transform vertices in absolute space
 			for(i=0; i < 8; i++) 
 			{
-				vTempBoxVertices[i] = new DVector3();
 				dMultiplyMat3Vec3(m_mBoxRot,m_avBoxVertices[i], vTempBoxVertices[i]);
 				dVector3Add(vTempBoxVertices[i], m_vBoxPos, m_avBoxVertices[i]);
 			}
@@ -898,24 +897,23 @@ private void _cldClipBoxToCylinder()
 			}
 
 			// find the vertices of box polygon
-			DVector3[] avPoints = new DVector3[4];
-			DVector3[] avTempArray1 = new DVector3[MAX_CYLBOX_CLIP_POINTS];
-			DVector3[] avTempArray2 = new DVector3[MAX_CYLBOX_CLIP_POINTS];
-			for (int ii = 0; ii < avPoints.length; ii++) avPoints[ii] = new DVector3();
-
-			int i=0;
-			for(i=0; i<MAX_CYLBOX_CLIP_POINTS; i++) 
-			{
-//				avTempArray1[i][0] = (0.0);
-//				avTempArray1[i][1] = (0.0);
-//				avTempArray1[i][2] = (0.0);
-				avTempArray1[i] = new DVector3();
-
-//				avTempArray2[i][0] = (0.0);
-//				avTempArray2[i][1] = (0.0);
-//				avTempArray2[i][2] = (0.0);
-				avTempArray2[i] = new DVector3();
-			}
+			DVector3[] avPoints = DVector3.newArray(4);
+			DVector3[] avTempArray1 = DVector3.newArray(MAX_CYLBOX_CLIP_POINTS);
+			DVector3[] avTempArray2 = DVector3.newArray(MAX_CYLBOX_CLIP_POINTS);
+
+//			int i=0;
+//			for(i=0; i<MAX_CYLBOX_CLIP_POINTS; i++) 
+//			{
+////				avTempArray1[i][0] = (0.0);
+////				avTempArray1[i][1] = (0.0);
+////				avTempArray1[i][2] = (0.0);
+//				avTempArray1[i] = new DVector3();
+//
+////				avTempArray2[i][0] = (0.0);
+////				avTempArray2[i][1] = (0.0);
+////				avTempArray2[i][2] = (0.0);
+//				avTempArray2[i] = new DVector3();
+//			}
 
 			DVector3 vAxis1 = new DVector3(), vAxis2 = new DVector3();
 
@@ -950,7 +948,7 @@ private void _cldClipBoxToCylinder()
 			DMatrix3 mCylinderInv = new DMatrix3();
 			dMatrix3Inv(m_mCylinderRot,mCylinderInv);
 
-			for(i=0; i<4; i++) 
+			for(int i=0; i<4; i++) 
 			{
 				dVector3Subtract(avPoints[i],vCylinderCirclePos,vTemp);
 				dMultiplyMat3Vec3(mCylinderInv,vTemp,avPoints[i]);
@@ -991,7 +989,7 @@ private void _cldClipBoxToCylinder()
 
 			if (nCircleSegment % 2 != 0)
 			{
-				for( i=0; i<iTmpCounter2; i++)
+				for(int i=0; i<iTmpCounter2; i++)
 				{
 					dMultiply0_331(vPoint,m_mCylinderRot,avTempArray2[i]);
 //					vPoint[0] += vCylinderCirclePos[0];
@@ -1027,7 +1025,7 @@ private void _cldClipBoxToCylinder()
 			}
 			else
 			{
-				for( i=0; i<iTmpCounter1; i++)
+				for(int i=0; i<iTmpCounter1; i++)
 				{
 					dMultiply0_331(vPoint,m_mCylinderRot,avTempArray1[i]);
 //					vPoint[0] += vCylinderCirclePos[0];
diff --git a/core/src/main/java/org/ode4j/ode/internal/CollideCylinderTrimesh.java b/core/src/main/java/org/ode4j/ode/internal/CollideCylinderTrimesh.java
index 29b7f28f..88a33b29 100644
--- a/core/src/main/java/org/ode4j/ode/internal/CollideCylinderTrimesh.java
+++ b/core/src/main/java/org/ode4j/ode/internal/CollideCylinderTrimesh.java
@@ -796,15 +796,11 @@ void _cldClipCylinderToTriangle(
 	{
 		int i = 0;
 		DVector3[] avPoints = { new DVector3(), new DVector3(), new DVector3() };//[3];
-		DVector3[] avTempArray1 = new DVector3[nMAX_CYLINDER_TRIANGLE_CLIP_POINTS];
-		DVector3[] avTempArray2 = new DVector3[nMAX_CYLINDER_TRIANGLE_CLIP_POINTS];
+		DVector3[] avTempArray1 = DVector3.newArray(nMAX_CYLINDER_TRIANGLE_CLIP_POINTS);
+		DVector3[] avTempArray2 = DVector3.newArray(nMAX_CYLINDER_TRIANGLE_CLIP_POINTS);
 
 //		dSetZero(avTempArray1[0][0],nMAX_CYLINDER_TRIANGLE_CLIP_POINTS * 4);
 //		dSetZero(avTempArray2[0][0],nMAX_CYLINDER_TRIANGLE_CLIP_POINTS * 4);
-		for (int ii = 0; ii < nMAX_CYLINDER_TRIANGLE_CLIP_POINTS; ii++) {
-			avTempArray1[ii] = new DVector3();
-			avTempArray2[ii] = new DVector3();
-		}
 
 		// setup array of triangle vertices
 		dVector3Copy(v0,avPoints[0]);
diff --git a/core/src/main/java/org/ode4j/ode/internal/CollideTrimeshBox.java b/core/src/main/java/org/ode4j/ode/internal/CollideTrimeshBox.java
index 3d1a1983..30d318d8 100644
--- a/core/src/main/java/org/ode4j/ode/internal/CollideTrimeshBox.java
+++ b/core/src/main/java/org/ode4j/ode/internal/CollideTrimeshBox.java
@@ -973,25 +973,25 @@ void _cldClipping(final DVector3C v0, final DVector3C v1, final DVector3C v2, fi
 				avPoints[3].eqSum( vRotCol,  tz1, vRotCol2,  tz2).add (vCenter);
 
 				// clip Box face with 4 planes of triangle (1 face plane, 3 egde planes)
-				DVector3[] avTempArray1 = new DVector3[9];
-				DVector3[] avTempArray2 = new DVector3[9];
+				DVector3[] avTempArray1 = DVector3.newArray(9);
+				DVector3[] avTempArray2 = DVector3.newArray(9);
 				DVector4 plPlane = new DVector4();
 
 				RefInt iTempCnt1 = new RefInt(0);
 				RefInt iTempCnt2 = new RefInt(0);
 
 				// zeroify vectors - necessary?
-				for(int i=0; i<9; i++) {
-					//	      avTempArray1[i][0]=0;
-					//	      avTempArray1[i][1]=0;
-					//	      avTempArray1[i][2]=0;
-					avTempArray1[i] = new DVector3();
-
-					//	      avTempArray2[i][0]=0;
-					//	      avTempArray2[i][1]=0;
-					//	      avTempArray2[i][2]=0;
-					avTempArray2[i] = new DVector3();
-				}
+//				for(int i=0; i<9; i++) {
+//					//	      avTempArray1[i][0]=0;
+//					//	      avTempArray1[i][1]=0;
+//					//	      avTempArray1[i][2]=0;
+//					avTempArray1[i] = new DVector3();
+//
+//					//	      avTempArray2[i][0]=0;
+//					//	      avTempArray2[i][1]=0;
+//					//	      avTempArray2[i][2]=0;
+//					avTempArray2[i] = new DVector3();
+//				}
 
 
 				// Normal plane
@@ -1102,23 +1102,23 @@ void _cldClipping(final DVector3C v0, final DVector3C v1, final DVector3C v2, fi
 
 				// CLIP Polygons
 				// define temp data for clipping
-				DVector3[] avTempArray1 = new DVector3[9];
-				DVector3[] avTempArray2 = new DVector3[9];
+				DVector3[] avTempArray1 = DVector3.newArray(9);
+				DVector3[] avTempArray2 = DVector3.newArray(9);
 
 				RefInt iTempCnt1 = new RefInt(), iTempCnt2 = new RefInt();
 
 				// zeroify vectors - necessary?
-				for(int i=0; i<9; i++) {
-					//	      avTempArray1[i][0]=0;
-					//	      avTempArray1[i][1]=0;
-					//	      avTempArray1[i][2]=0;
-					avTempArray1[i] = new DVector3();
-
-					//	      avTempArray2[i][0]=0;
-					//	      avTempArray2[i][1]=0;
-					//	      avTempArray2[i][2]=0;
-					avTempArray2[i] = new DVector3();
-				}
+//				for(int i=0; i<9; i++) {
+//					//	      avTempArray1[i][0]=0;
+//					//	      avTempArray1[i][1]=0;
+//					//	      avTempArray1[i][2]=0;
+//					avTempArray1[i] = new DVector3();
+//
+//					//	      avTempArray2[i][0]=0;
+//					//	      avTempArray2[i][1]=0;
+//					//	      avTempArray2[i][2]=0;
+//					avTempArray2[i] = new DVector3();
+//				}
 
 				// clip triangle with 5 box planes (1 face plane, 4 edge planes)
 
diff --git a/core/src/main/java/org/ode4j/ode/internal/DxBody.java b/core/src/main/java/org/ode4j/ode/internal/DxBody.java
index 4f640467..cfa8ca3f 100644
--- a/core/src/main/java/org/ode4j/ode/internal/DxBody.java
+++ b/core/src/main/java/org/ode4j/ode/internal/DxBody.java
@@ -818,12 +818,8 @@ void dBodySetAutoDisableAverageSamplesCount (int average_samples_count)
 		}
 		if(adis.average_samples > 0)
 		{
-			average_lvel_buffer = new DVector3[adis.average_samples];
-			for (int i = 0; i < average_lvel_buffer.length; i++) 
-				average_lvel_buffer[i] = new DVector3();
-			average_avel_buffer = new DVector3[adis.average_samples];
-			for (int i = 0; i < average_avel_buffer.length; i++) 
-				average_avel_buffer[i] = new DVector3();
+			average_lvel_buffer = DVector3.newArray(adis.average_samples);
+			average_avel_buffer = DVector3.newArray(adis.average_samples);
 		}
 		else
 		{
diff --git a/core/src/main/java/org/ode4j/ode/internal/joints/DxJointAMotor.java b/core/src/main/java/org/ode4j/ode/internal/joints/DxJointAMotor.java
index a6e0ad37..c4570354 100644
--- a/core/src/main/java/org/ode4j/ode/internal/joints/DxJointAMotor.java
+++ b/core/src/main/java/org/ode4j/ode/internal/joints/DxJointAMotor.java
@@ -537,7 +537,7 @@ AMotorMode dJointGetAMotorMode()
 
 	void dJointAddAMotorTorques( double torque1, double torque2, double torque3 )
 	{
-		DVector3[] axes = new DVector3[3];
+		DVector3[] axes = new DVector3[]{new DVector3(), new DVector3(), new DVector3()};
 
 		if ( _num == 0 )
 			return;
diff --git a/core/src/main/java/org/ode4j/ode/internal/joints/DxJointLMotor.java b/core/src/main/java/org/ode4j/ode/internal/joints/DxJointLMotor.java
index b4c91fd4..de7e3f13 100644
--- a/core/src/main/java/org/ode4j/ode/internal/joints/DxJointLMotor.java
+++ b/core/src/main/java/org/ode4j/ode/internal/joints/DxJointLMotor.java
@@ -111,10 +111,7 @@ void getSureMaxInfo( SureMaxInfo info )
 	getInfo2( double worldFPS, double worldERP, DxJoint.Info2Descr info )
 	{
 		int row = 0;
-		DVector3[] ax = new DVector3[3];
-		for (int i = 0; i<3; i++ ) {
-			ax[i] = new DVector3();
-		}
+		DVector3[] ax = new DVector3[]{new DVector3(), new DVector3(), new DVector3()};
 
 		computeGlobalAxes( ax );
 
diff --git a/demo/src/main/java/org/ode4j/demo/DemoBoxstack.java b/demo/src/main/java/org/ode4j/demo/DemoBoxstack.java
index 24271520..c28c1805 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoBoxstack.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoBoxstack.java
@@ -344,8 +344,8 @@ public void command (char cmd)
 				DMass m2 = OdeHelper.createMass();
 				m.setZero();
 
-				DVector3[] dpos = new DVector3[GPB];	// delta-positions for encapsulated geometries
-				DMatrix3[] drot = new DMatrix3[GPB];
+				DVector3[] dpos = DVector3.newArray(GPB);	// delta-positions for encapsulated geometries
+				DMatrix3[] drot = DMatrix3.newArray(GPB);
 
 				// set random delta positions
 				for (j=0; j<GPB; j++) {
@@ -369,7 +369,6 @@ public void command (char cmd)
 						m2.setCapsule(DENSITY,3,radius,length);
 					}
 
-					drot[k] = new DMatrix3();
 					dRFromAxisAndAngle (drot[k],dRandReal()*2.0-1.0,dRandReal()*2.0-1.0,
 							dRandReal()*2.0-1.0,dRandReal()*10.0-5.0);
 					m2.rotate(drot[k]);
diff --git a/demo/src/main/java/org/ode4j/demo/DemoCollision.java b/demo/src/main/java/org/ode4j/demo/DemoCollision.java
index 0f492c5a..16ad84bf 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoCollision.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoCollision.java
@@ -1193,8 +1193,7 @@ private static boolean testBoxesTouch2 (final DVector3 p1, final DMatrix3 R1,
 				if (fd==0) { k1 = 1; k2 = 2; }
 				if (fd==1) { k1 = 0; k2 = 2; }
 				if (fd==2) { k1 = 0; k2 = 1; }
-				DVector3 fp[]=new DVector3[4],tmp=new DVector3();
-				for (int z=0; z < fp.length; z++) fp[z] = new DVector3();
+				DVector3 fp[] = DVector3.newArray(4), tmp=new DVector3();
 				k=0;
 				for (j1=-1; j1<=1; j1+=2) {
 					for (j2=-1; j2<=1; j2+=2) {
diff --git a/demo/src/main/java/org/ode4j/demo/DemoHeightfield.java b/demo/src/main/java/org/ode4j/demo/DemoHeightfield.java
index f4fcdcf8..84b9db15 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoHeightfield.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoHeightfield.java
@@ -370,14 +370,12 @@ public void command (char cmd) {
 				DMass m2 = OdeHelper.createMass();
 				m.setZero ();
 
-				DVector3[] dpos = new DVector3[GPB];	// delta-positions for encapsulated geometries
-				DMatrix3[] drot = new DMatrix3[GPB];
+				DVector3[] dpos = DVector3.newArray(GPB);	// delta-positions for encapsulated geometries
+				DMatrix3[] drot = DMatrix3.newArray(GPB);
 
 				// set random delta positions
 				for (j=0; j<GPB; j++) {
-					dpos[j] = new DVector3();
 					for (k=0; k<3; k++) dpos[j].set(k, dRandReal()*0.3-0.15);
-					drot[j] = new DMatrix3();
 				}
 
 				for (k=0; k<GPB; k++) {
diff --git a/demo/src/main/java/org/ode4j/demo/DemoI.java b/demo/src/main/java/org/ode4j/demo/DemoI.java
index 2fa242c3..7791a553 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoI.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoI.java
@@ -117,7 +117,7 @@ private static void reset_test()
 		int i;
 		DMass m = OdeHelper.createMass(), anchor_m=OdeHelper.createMass();
 		//float q[NUM][3], pm[NUM];	// particle positions and masses
-		DVector3[] q = new DVector3[NUM];
+		DVector3[] q = DVector3.newArray(NUM);
 		DVectorN pm = new DVectorN(NUM);
 		DVector3 pos1 = new DVector3(1,0,1);	// point of reference (POR)
 		DVector3 pos2 = new DVector3(-1,0,1);	// point of reference (POR)
@@ -125,7 +125,6 @@ private static void reset_test()
 		// make random particle positions (relative to POR) and masses
 		for (i=0; i<NUM; i++) {
 			pm.set(i, dRandReal()+0.1);
-			q[i] = new DVector3();
 			q[i].set0(dRandReal()-0.5);
 			q[i].set1(dRandReal()-0.5);
 			q[i].set2(dRandReal()-0.5);
diff --git a/demo/src/main/java/org/ode4j/demo/DemoMovingTrimesh.java b/demo/src/main/java/org/ode4j/demo/DemoMovingTrimesh.java
index 63b789e0..3a69b81c 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoMovingTrimesh.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoMovingTrimesh.java
@@ -255,14 +255,12 @@ else if (cmd == 'x') {
 				DMass m2 = OdeHelper.createMass();
 				m.setZero ();
 
-				DVector3[] dpos = new DVector3[GPB];//[3];	// delta-positions for encapsulated geometries
-				DMatrix3[] drot = new DMatrix3[GPB];
+				DVector3[] dpos = DVector3.newArray(GPB);//[3];	// delta-positions for encapsulated geometries
+				DMatrix3[] drot = DMatrix3.newArray(GPB);
 
 				// set random delta positions
 				for (j=0; j<GPB; j++) {
-					dpos[j] = new DVector3();
 					for (k=0; k<3; k++) dpos[j].set(k, dRandReal()*0.3-0.15 );
-					drot[j] = new DMatrix3();
 				}
 
 				for (k=0; k<GPB; k++) {
diff --git a/demo/src/main/java/org/ode4j/demo/DemoOde.java b/demo/src/main/java/org/ode4j/demo/DemoOde.java
index 30abd874..11706788 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoOde.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoOde.java
@@ -810,7 +810,7 @@ private void testMassFunctions()
 		int i,j;
 		//  double q[NUMP][3];		// particle positions
 		//double[][] q = new double[NUMP][3];		// particle positions
-		DVector3[] q = new DVector3[NUMP];		// particle positions
+		DVector3[] q = DVector3.newArray(NUMP);		// particle positions
 		//  double pm[NUMP];		// particle masses
 		double[] pm = new double[NUMP];		// particle masses
 		DMass m1 = new DxMass(),m2 = new DxMass();
@@ -887,7 +887,6 @@ private void testMassFunctions()
 		// translate and repeat.
 		for (i=0; i<NUMP; i++) {
 			pm[i] = dRandReal()+0.5;
-			q[i] = new DVector3();
 			for (j=0; j<3; j++) {
 				q[i].set(j, 2.0*(dRandReal()-0.5) );
 			}
diff --git a/demo/src/main/java/org/ode4j/demo/DemoSpaceStress.java b/demo/src/main/java/org/ode4j/demo/DemoSpaceStress.java
index d4c2a567..abbdc2b6 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoSpaceStress.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoSpaceStress.java
@@ -70,7 +70,7 @@
 public class DemoSpaceStress extends dsFunctions {
 	// some constants
 
-	private static final int NUM = 10000;			// max number of objects
+	private static final int NUM = 2000;			// max number of objects
 	private static final float DENSITY = 5.0f;		// density of all objects
 	private static final int GPB = 3;			// maximum number of geometries per body
 	private static final int MAX_CONTACTS = 4;		// maximum number of contact points per body
@@ -246,16 +246,14 @@ public void command (char cmd) {
 				DMass m2 = OdeHelper.createMass();
 				m.setZero ();
 
-				DVector3[] dpos = new DVector3[GPB];	// delta-positions for encapsulated geometries
-				DMatrix3[] drot = new DMatrix3[GPB];
+				DVector3[] dpos = DVector3.newArray(GPB);	// delta-positions for encapsulated geometries
+				DMatrix3[] drot = DMatrix3.newArray(GPB);
 
 				// set random delta positions
 				for (j=0; j<GPB; j++) {
-					dpos[j] = new DVector3();
 					for (k=0; k<3; k++) {
 						dpos[j].set(k, dRandReal()*0.3-0.15 );
 					}
-					drot[j] = new DMatrix3();
 				}
 
 				for (k=0; k<GPB; k++) {
diff --git a/demo/src/main/java/org/ode4j/demo/DemoTrimesh.java b/demo/src/main/java/org/ode4j/demo/DemoTrimesh.java
index 368b7358..170df514 100644
--- a/demo/src/main/java/org/ode4j/demo/DemoTrimesh.java
+++ b/demo/src/main/java/org/ode4j/demo/DemoTrimesh.java
@@ -249,16 +249,14 @@ else if (cmd == 'x') {
 				DMass m2 = OdeHelper.createMass();
 				m.setZero ();
 
-				DVector3[] dpos = new DVector3[GPB];	// delta-positions for encapsulated geometries
-				DMatrix3[] drot = new DMatrix3[GPB]; 
+				DVector3[] dpos = DVector3.newArray(GPB);	// delta-positions for encapsulated geometries
+				DMatrix3[] drot = DMatrix3.newArray(GPB); 
 
 				// set random delta positions
 				for (j=0; j<GPB; j++) {
-					dpos[j] = new DVector3();
 					for (k=0; k<3; k++) {
 						dpos[j].set(k, dRandReal()*0.3-0.15 );
 					}
-					drot[j] = new DMatrix3();
 				}
 
 				for (k=0; k<GPB; k++) {
diff --git a/demo/src/test/java/org/ode4j/tests/TestIssue8_Gimpact.java b/demo/src/test/java/org/ode4j/tests/TestIssue0008_Gimpact.java
similarity index 99%
rename from demo/src/test/java/org/ode4j/tests/TestIssue8_Gimpact.java
rename to demo/src/test/java/org/ode4j/tests/TestIssue0008_Gimpact.java
index 78b025b9..ab67b76a 100644
--- a/demo/src/test/java/org/ode4j/tests/TestIssue8_Gimpact.java
+++ b/demo/src/test/java/org/ode4j/tests/TestIssue0008_Gimpact.java
@@ -45,7 +45,7 @@
 import org.ode4j.ode.OdeConstants;
 import org.ode4j.ode.OdeHelper;
 
-public class TestIssue8_Gimpact {
+public class TestIssue0008_Gimpact {
 
     private DWorld world;
     private DSpace space;
diff --git a/demo/src/test/java/org/ode4j/tests/TestIssue0017_NpeInSetTorques.java b/demo/src/test/java/org/ode4j/tests/TestIssue0017_NpeInSetTorques.java
new file mode 100644
index 00000000..5c499768
--- /dev/null
+++ b/demo/src/test/java/org/ode4j/tests/TestIssue0017_NpeInSetTorques.java
@@ -0,0 +1,18 @@
+package org.ode4j.tests;
+
+import org.junit.Test;
+import org.ode4j.ode.DAMotorJoint;
+import org.ode4j.ode.DWorld;
+import org.ode4j.ode.OdeHelper;
+
+public class TestIssue0017_NpeInSetTorques {
+
+	@Test
+	public void test() {
+		DWorld w = OdeHelper.createWorld();
+		DAMotorJoint j = OdeHelper.createAMotorJoint(w);
+		j.setNumAxes(3);
+		j.addTorques( 1, 2, 3 );
+	}
+	
+}