difference between stored procedures and user defined functions

A function always returns a value, and can not perform DML statements (INSERT/UPDATE/DELETE).
A stored procedure can not return a value - you need to use an OUT parameter - and can run DML statements.

Advantage of Using a Function vs a Stored Procedure?

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Aside from the comparison above, they are equal. But given the comparison, depending on what you need to do it's likely you will use a stored procedure more often than you will a function.

http://stackoverflow.com/questions/2039936/difference-between-stored-procedures-and-user-defined-functions

Testing Private Methods in Java

I’ve been writing a lot of Java lately, and a lot of tests. We always write tests, right? Alas, no cool record-and-playback stuff like FlexMonkey or FoneMonkey, just plain old JUnit 4 tests with plently of Hamcrest goodness.

Suddenly, I realized that I really needed to test some private methods. So, a quick google for “testing private methods java” brings up a good article by Bill Venners. He lists all possible options to test private methods:

1. Don’t test private methods
2. Give the methods package access
3. Use a nested test class
4. Use reflection

Basically, the only real one is #4, use reflection. Bill didn’t give me the exact code I needed, so lots of googling later I realized that the world is filled with opinionated people (like me), and boy do they love to talk about #1. I just wanted some code, not a lecture, so I had to write my own code. Here is that code for anyone else that just wants to test private methods.

Imagine you have a class MyClass and it has a private method, myMethod(). Sorta like this:

public class MyClass {
    private String myMethod(String s) {
        return s;
    }
}

Then you could use reflection to invoke the method like this:

MyClass myClass = new MyClass();
Method method = MyClass.class.getDeclaredMethod("myMethod", String.class);
method.setAccessible(true);
String output = (String) method.invoke(myClass, "some input");

The real magic is setAccessible(true) which allows the private method to be called outside the class. And shazam, I can now test all my private methods. I was really hoping JUnit 4 would provide some additional facilities specifically for testing private methods, but not luck.

http://saturnboy.com/2010/11/testing-private-methods-in-java/

How do you unit test private methods?

You generally don't unit test private methods directly. Since they are private, consider them an implementation detail. Nobody is ever going to call one of them and expect it to work a particular way.
You should instead test your public interface. If the methods that call your private methods are working as you expect, you then assume by extension that your private methods are working correctly.

http://programmers.stackexchange.com/questions/100959/how-do-you-unit-test-private-methods

What is the difference between an ordered and a sorted collection?

An ordered collection means that the elements of the collection have a specific order. The order is independent of the value. A List is an example.

A sorted collection means that not only does the collection have order, but the order depends on the value of the element. A SortedSet is an example.

In contrast, a collection without any order can maintain the elements in any order. A Set is an example.

http://stackoverflow.com/questions/1084146/what-is-the-difference-between-an-ordered-and-a-sorted-collection

Difference between JSP include directive and JSP include action

• <%@ include file=”filename” %> is the JSP include directive.
  At JSP page translation time, the content of the file given in the include directive is ‘pasted’ as it is, in the place where the JSP include directive is used. Then the source JSP page is converted into a java servlet class. The included file can be a static resource or a JSP page. Generally JSP include directive is used to include header banners and footers. The JSP compilation procedure is that, the source JSP page gets compiled only if that page has changed. If there is a change in the included JSP file, the source JSP file will not be compiled and therefore the modification will not get reflected in the output.
• is the JSP include action element.
  The jsp:include action element is like a function call. At runtime, the included file will be ‘executed’ and the result content will be included with the soure JSP page. When the included JSP page is called, both the request and response objects are passed as parameters. If there is a need to pass additional parameters, then jsp:param element can be used. If the resource is static, its content is inserted into the calling JSP file, since there is no processing needed.

http://javapapers.com/jsp/difference-between-jsp-include-directive-and-jsp-include-action/

difference between jsp forward and redirect

• redirect sets the response status to 302, and the new url in a Location header, and sends the response to the browser. Then the browser, according to the http specification, makes another request to the new url
• forward happens entirely on the server. The servlet container just forwards the same request to the target url, without the browser knowing about that. Hence you can use the same request attributes and the same request parameters when handling the new url. And the browser won't know the url has changed (because it has happened entirely on the server)
   

http://stackoverflow.com/questions/6068891/difference-between-jsp-forward-and-redirect

What is the difference between a process and a thread

Process:

• An executing instance of a program is called a process.
• Some operating systems use the term ‘task‘ to refer to a program that is being executed.
• A process is always stored in the main memory also termed as the primary memory or random access memory.
• Therefore, a process is termed as an active entity. It disappears if the machine is rebooted.
• Several process may be associated with a same program.
• On a multiprocessor system, multiple processes can be executed in parallel.
• On a uni-processor system, though true parallelism is not achieved, a process scheduling algorithm is applied and the processor is scheduled to execute each process one at a time yielding an illusion of concurrency.
• Example: Executing multiple instances of the ‘Calculator’ program. Each of the instances are termed as a process.

Thread:

• A thread is a subset of the process.
• It is termed as a ‘lightweight process’, since it is similar to a real process but executes within the context of a process and shares the same resources allotted to the process by the kernel (See kquest.co.cc/2010/03/operating-system for more info on the term ‘kernel’).
• Usually, a process has only one thread of control ? one set of machine instructions executing at a time.
• A process may also be made up of multiple threads of execution that execute instructions concurrently.
• Multiple threads of control can exploit the true parallelism possible on multiprocessor systems.
• On a uni-processor system, a thread scheduling algorithm is applied and the processor is scheduled to run each thread one at a time.
• All the threads running within a process share the same address space, file descriptor, stack and other process related attributes.
• Since the threads of a process share the same memory, synchronizing the access to the shared data withing the process gains unprecedented importance.

I borrowed the above info from the Knowledge Quest! blog available at:http://kquest.co.cc/2010/03/program-process-task-thread/

http://stackoverflow.com/questions/200469/what-is-the-difference-between-a-process-and-a-thread