Undefined function 'javaaddpath' for input arguments of type 'cell'

Question

I am currently call Matlab object in my java code .

The code of matlab is easy like this

function idx = clustering(W, k)
    degs = sum(W, 2);
    D = sparse(1:size(W, 1), 1:size(W, 2), degs);
    L = D-W;
    [V,dummy] = eigs(W,k,'sr');
    idx = kmeans(V, k);
end

It is easy to use the object Clustering in Java.

I generate an object with code like this,

Spclustering specClusteringcol = null;

try {
    specClusteringcol = new Spclustering();
} catch (MWException e) {
    e.printStackTrace();
}

.......do some thing

if(specClusteringcol!=null)
  specClusteringcol.dispose();

If I run simple demo in a single thread , this works correctly.

However, if I run some time cost task

the runtime will give out an exception

Undefined function 'javaaddpath' for input arguments of type 'cell'.

Why this happens? How to solve it?