The first thing to check would be the number of elements you're passing in to drawArrays/drawElements to see if you're going past the end of the array. But if you've switched straight from an existing app this is probably ok.

In terms of NIO specific, its very easy to forget to call .clear and .rewind before you fill it with data again, and end up putting data in places you don't expect.

Short of that, hows about seeing some code?

Here's my code to set the array:
where the varray is a set of {x,y,z} and tarray is a set of {s,t}

  public void setVertexArrayPtr(float[] varray)              {
      FloatBuffer f = net.java.games.jogl.util.BufferUtils.newFloatBuffer(varray.length);
      f.put(varray);
      gl.glVertexPointer(3, GL.GL_FLOAT, 0, f);
  }
  public void setTextureArrayPtr(float[] tarray)             {
      FloatBuffer f = net.java.games.jogl.util.BufferUtils.newFloatBuffer(tarray.length);
      f.put(tarray);
      gl.glTexCoordPointer(2, GL.GL_FLOAT, 0, f);
  }

Am I calling it correctly?
Aaron