I think, getter and setter shouldn't be static, but the property "container" yes. Hope this code to be a correct JavaBean:

import java.io.*;
public class SingletonBean implements Serializable {
    private static String sample;

    public SingletonBean() {
    }
    public String getSample() {
        return sample;
    }
    public void setSample(String newSample) {
        sample = newSample;
    }
}

Static properties/methods are not recognized to be properties/metods of a JavaBean.
To define a singleton bean you can code it as the following example:

class SimpleSingleton {
    private static SimpleSingleton instance;
    private String sampleProperty;

    //The constructor shall be protected or private 
    //friendly and public is not enough 
    //to prevent client's instantiation.
    protected SimpleSingleton() {}

    public static SimpleSingleton getInstance() {
        if (null == instance) {
            instance = new SimpleSingleton();
        }
        return instance;
    }

    public void setSampleProperty(String newSampleProperty) {
        sampleProperty = newSampleProperty;
    }
    public String getSampleProperty() {
        return sampleProperty;
    }
}

public class ExampleSingleton {

    public static void main(String[] args) {
        SimpleSingleton one = SimpleSingleton.getInstance();
        one.setSampleProperty("Always the same!");

        //SimpleSingleton anotherOne = new SimpleSingleton(); //you cannot do that!
        SimpleSingleton anotherOne = SimpleSingleton.getInstance();
        System.out.println("Property of another one : " +
            anotherOne.getSampleProperty());
    }
}

There is nothing that stops you from creating static methods within a Bean class. However, they won't be treated as properties. Also not supported is creating beans from methods other than the constructor.