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I want to use java variable in single jsp page

<%!
public void runJavaMethod(int id)
{
%>
<%
try{
String icd = request.getParameter("icd");
String inm = request.getParameter("inm");
String istk = request.getParameter("istock");
String sstk = request.getParameter("sstock");
String upr = request.getParameter("uprice");
String spr = request.getParameter("sprice");
r = s.executeQuery("select * from itemsyncdata");
while(r.next())
{
s.executeUpdate("update itemsyncdata set itemcode='"+icd+"',itemname='"+inm+"',instock='"+istk+"',storestock='"+sstk+"',unitprice='"+upr+"',storeprice='"+spr+"' where id='"+a+"'");
}
}
catch(Exception e)
{
e.printStackTrace();
}
%>
<%!} %>
And I am Calling Function from html like
<input type="submit" id="btnSync" value="Sync" class="button" name="Sync" onclick="<%runJavaMethod(r.getInt(1));%>"/>
So We want runJavaMethod Parameter.

onclick="<%runJavaMethod(r.getInt(1));%>"/>
HTML/Javascript Plays on client side and JSP/Java plays on server side.
Simply you can't. You might misunderstand that JSP and HTML/JavaScript existed on same document. Yes but JSP part compiles on server side itself comes to client.
What you can do is you have to make a server request. Most probably look at Ajax requests.

You are trying to mix up two languages i.e., Java and Javascript/html together i.e., onclick is a Javascript event and you can't call runJavaMethod from Javascript.
In simple words, you can't directly call a Java method (present inside the scriptlet) using Javascript because all of your JSP code produces (becomes) html when it is loaded from the server.
So, if you have to fix the issue, upon onclick, you need to call an URL which hits a servlet/controller method on the server to do the job (i.e., executes the business logic).
One more important point is that Scriptlets are legacy code and I strongly suggest not use them to generate or manage the html content, rather use JSTL so that there will be a clear separation between the concerns (i.e., business logic and user interface requirements).
Also, I strongly suggest you read the JSP best practices from here and follow them.

You are mixing to two different things. JSP is server side code and it's rendered response is the HTML that is send back to the browser.Javascript is pure client side in your case.
If you really want invoke a server side processing than create a simple Java script function with Ajax call and get response back which u can use it.
I suggest send all the logic of JSP in backend class not a good practice to put in the jsp. JSP is ideally for UI design.

Assign var to String inside the same function

I have this code:
<script type="text/javascript">
function foo() {
var test =///value;
<!--and i jave java code inside this script!-->
<% String str= // i want to assign it to test value%>
}
</script>
How can i assign test to str ??

How can i assign test to str ??
No simply you cannot.
Java plays on server side and javascript on server side. A client doesn't execute the java code.
You can assign a java value to javascript variable with jsp or Expression language on server side.
To send a javascript value to java you have to make a server request, So the server process your string and send the results back to client.
Most probably you are looking for AJAX request.
Ajax.
Do not confuse that JSP and java script existed on same document(or file). Yes but JSP part compiles on server side and JavaScript executes by browser.
A clear cut example found here for a start.

call a java method when Click on a html button without using javascript

i work on JSP and i want to call a java method(Function) on Click on a html button without using<script></script>.how?
i try to write this code:
<button onclick="<%po.killThread();%>">
<font size="4">Kill</font>
</button>
but it doesn't work... so please help me.
thanks

You're misunderstanding how server-side programming works. When you load that page, the webserver will get to the line <button onclick="<%po.killThread();%>"> and will immediately parse and execute the JSP snippet, in your case po.killThread(), and replace everything between the <% and %> with the return value of that method, if any. And all these happens on server side, before client receives any thing. (Note that this will only happen if that page is not already been loaded and compiled into a Servlet by the server.)
Thus, the HTML that client receives, will be something like, <button onclick="some return value or nothing">, which means that nothing will happen when you press the button. If you want to execute further JSP commands on the button press you will need to make a new request to the server - for example, by redirecting the page.

This will call the function killThread when you open the website.
Try to redirect to another jsp which calls the function.

this will not run at all because after the jsp page is compiled it will return the po.killThread() value but will not call this method
You can see this by viewing the page source

JSP is a server-side technology. Did I say server-side?
In order to understand how JSP works and to clear any misconception, JavaRanch Journal (Vol. 4, No. 2): The Secret Life of JavaServer Pages is a very good read.
An excerpt from the same,
JSP is a templating technology best-suited to the delivery of dynamic text documents in a format that is white-space agnostic.
Template text within a JSP page (which is anything that is not a dynamic element), to include all white-space and line terminators, becomes part of the final document.
All dynamic elements in a JSP are interpreted on the server and once the document is sent to the client, no further dynamic interaction is possible (short of requesting the same or another document).

If you are using JSPs, then to perform some method calles, you will have to write a servlet and then call the method in doPost or doGet method of servlet.
On the other hand, if you want to make things simpler, use JSF framework which will help you achieve your objective as JSF supports event handling.

Communicating between JavaScript and Servlet

In my JSP page I have DIV.
<div id="100">
ALI
</div>
When I click on this DIV...
$("#100").click(function(){
});
...I need to send the value of the id 100, to a servlet, so that the servlet makes some database java codes, and returns for example, either 1 or 0. How can I do that? and is this the proper way?

Using Ajax, you should call your server using a URL similar to this:
http://localhot:8080/youAppContext/yourServer?id=100
Then, in the servler side, you should retrieve the value that will be in the request with the name "id"
There are out there many tool as jQuery that can help you to do the Ajax petition.
Edited
Well, here you can find a very simple Ajax example using jQuery. In the example, instead call a file (test1.txt) you should invoke a URL (as I described above). Of course, you will need to write some JS code to build your URL (where id be a variable). Once task is done in servlet side, you can return whatever, for example: "done" and display or not this information the HTML as it is done in the example.
Take a look to this Web, there are many links that can help you.

get the value using
var value = $("#100").html();
and pass it to servlet using AJAX

How I can get my DB values inside the tag of my Jquery UI pligin?

$(function() {
var availableTags = ["ActionScript", "AppleScript", "Scheme"];
$("#tags").autocomplete({
source: availableTags
});
I don want the values inside the tags. i have a JS page i need to make a function for connecting my DB to the auto complete plugin. How can i do it suggestions Please.
Thanks in Advance..

You can not connect to a database using only JavaScript and you should never show your database values in JavaScript as everybody can read them.
You have to use a server side script to connect to your database, resolving the autocomplete values and responding them to the autocomplete plugin.
So in gerenal you don't use a local "source" with the suggestions, but a server side script and getting the values through ajax calls:
$("#tags").autocomplete('url_to_server_side_script');
EDIT: So i looks like it is a JSP page. After getting the values wihtin the function, you have to create an output (and use the "reponse" to send it to the client) with each value in a new line looking like this:
ActionScript
AppleScript
Scheme
You can even use HTML to markup the match of the query string (let's asume it was "Sc"):
Action<em>Sc</em>ript
Apple<em>Sc</em>ript
<em>Sc</em>heme