HELP ...DONT UNDERSTAND Error

[ask4soteria]

//this is my hash table function
 public void hashTable(String s, int randX) {



        int key1 = (randX % 9);
        int c = (randX % 5) + 1;
        int i = 0;
        Integer check;

       
        check = (Integer) hashtable.get(key1);
              if (isEmpty(check)) {

            hashtable.put(key1, s);

        }
 else{
            System.out.println("is it empty?????" + isEmpty(check));
 }
    }

// this is my boolean check
    public static boolean isEmpty(Integer p) {
        boolean isnull = false;
        // System.out.println("ok here p is : " + p);
        //any variables you would need
        if (p == null) //{
        {
            System.out.println("it is true");
            isnull = true;
        }

        return isnull;

    }

for some reason once the boolean fails it gives me this error





Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
at HashFunc.hashTable(HashFunc.java:237)
at HashFunc.actionPerformed(HashFunc.java:166)
at javax.swing.AbstractButton.fireActionPerformed(Abs tractButton.java:2028)
at javax.swing.AbstractButton$Handler.actionPerformed (AbstractButton.java:2351)
at javax.swing.DefaultButtonModel.fireActionPerformed (DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultB uttonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseRe leased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.jav a:6352)
at javax.swing.JComponent.processMouseEvent(JComponen t.java:3267)
at java.awt.Component.processEvent(Component.java:611 7)
at java.awt.Container.processEvent(Container.java:208 5)
at java.awt.Component.dispatchEventImpl(Component.jav a:4714)
at java.awt.Container.dispatchEventImpl(Container.jav a:2143)
at java.awt.Component.dispatchEvent(Component.java:45 44)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:4621)
at java.awt.LightweightDispatcher.processMouseEvent(C ontainer.java:4282)
at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:4212)
at java.awt.Container.dispatchEventImpl(Container.jav a:2129)
at java.awt.Window.dispatchEventImpl(Window.java:2478 )
at java.awt.Component.dispatchEvent(Component.java:45 44)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 635)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:296)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:196)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:188)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:122)

[Zack]

I can't see what your hashtable variable is or what put() is supposed to do, but I can tell that put() is trying to accept 2 integer variables and is receiving an integer and a string ( hashtable.put(key1, s); ).

[ask4soteria]

ok put() is accepting two variables. an int(key) and a string(item). the problem is on my boolean check " isEmpty()

whenever i fails it never goes true it just spits the error out.

// i used the inbuilt hash table function.
Hashtable hashtable = new Hashtable(9);

hashtable.put(key1, s);// this put is part of the lib.

[DarrylBurke]

put() is trying to accept 2 integer variables and is receiving an integer and a string

I think it's failing on

check = (Integer) hashtable.get(key1);

with

ClassCastException: java.lang.String cannot be cast to java.lang.Integer

Evidently that's a Hashtable<Integer, String> and the reference returned from get(...) can't be cast to an Integer.

db

[ask4soteria]

Ok so how do i fix it?

Thank you

[ask4soteria]

also to make that an object i have to type cast it as (Integer) if not its not gonna work..

if have any other ideas pls lemme know thank you

[Vinod Mukundan]

The solution depends upon wat does hashtable.get(key1) return ? does it return a valid value parsable to Integer ???? .
Why don't u use a Hashtable<Integer,Integer> instead.