排序FilteredList时出现UnsupportedOperationException

Question

// Restart the force layout.
  var force.nodes(nodes) 
        .links(links)
        .charge(-1000)
        .linkDistance(120)
        .alpha(-15)
        .start();   

    var link = vis.selectAll(".link")
        .data(links);

    link.enter().insert("svg:line", ".node")
        .attr("class", "link")
        .style("stroke", "#ccc")
        .attr("cursor", "pointer")
        .style("stroke-width", "0")
        .style("stroke-width", function(d) { return d.weight;})
        .on("mouseover", function() { d3.select(this).style("stroke", "#555555").attr("stroke-opacity", "1.0").attr("stroke-width","10");})
        .on("mouseout", function() { d3.select(this).style("stroke", "#ccc").attr("stroke-opacity", "1.0").attr("stroke-width","4") });

    link.exit().remove();

    var node = vis.selectAll("g.node")
        .data(nodes)

    var groups = node.enter().append("g")
        .attr("class", "node")
        .attr("id", function (d) {
            return d.entityType;
        })
        .on('click', click)

    groups.append("circle")
       .attr("cursor", "pointer")
       .style("fill", function(d) { return color(d.entityType); })
       .style("fill", "#fff")
       .style("stroke-width", "0")
       .style("stroke", "#ddd")
     .attr("r", 20);

 groups.append("text")
        .attr("dy", 18)
        .style("font-size", "2.5px")
        .style("text-anchor", "middle")
        .style('fill','#000')
        .attr("refX", 15)
        .attr("refY", -1.5)
        .text(function (d) {
            return d.text;
        });

node.exit().remove();

 force.on("tick", function () {
        link.attr("x1", function (d) {
            return d.source.x;
        })
            .attr("y1", function (d) {
            return d.source.y;
        })
            .attr("x2", function (d) {
            return d.target.x;
        })
            .attr("y2", function (d) {
            return d.target.y;
        });

        node.attr("transform", function(d) {
            return "translate(" + d.x + "," + d.y + ")";
        });

我得到了不支持的操作异常java.util.AbstractList.set（AbstractList.java:132） 我可以知道代码有什么问题吗？