JAVABEANS error cannot find symbol

I try to use javabeans reflection for set/get value of property by name of that property.

When I try to compile this code

class TestReflection
{
    public TestReflection()
    {
    }

    private Integer field;

    public Integer getField()
    {
        return this.field;
    }

    public void setField(Integer x)
    {
        this.field = x;
    }

}

//  .
//  .
//  .


TestReflection ref = new TestReflection();
Object value = new PropertyDescriptor("field",
    ref.class).getReadMethod().invoke(ref); // ERROR

I got this error:

Test.java:84: error: cannot find symbol
                            ref.class).getReadMethod().invoke(ref);
  symbol: class ref

How can I fix that error?