Java clipboard invoke paste operation

Question

I would like to invoke a paste operation with my java application. Is this possible without using Robot?

For example, the application would invoke a paste operation every so often, so when I am writing in notepad, I would see the contents of my clipboard.

JAVA APP                       Notepad
clipboard.paste()  -------->   clipboardContents

Answer 1

It sounds as if you're trying to use Java to interact or partially drive another application (such as Windows NotePad) and paste to that application, and if so there are several possible solutions, one being use of Robot, another having Java make operating system calls, though this can't be done directly with just core Java and would require use of either JNI, JNA or other platform-specific non-core utility programs such as AutoIt (if this is for Windows).

Why are you dead set on not using Robot? Can you explain your needs in greater detail?

Edit
regarding your comment:

I want to explore alternatives to Robot, as my client irrationally rejects Robot.

Since this appears to be for a Windows platform, you might consider exploring the Windows API and the API for whatever non-Java program you're trying to drive (if one exists), and then using JNA to interact with it. The Windows User32.dll would allow you to get the Window handle (hWnd) of the application that you're trying to drive, which may be necessary for this to work.

It's hard to give more specific advice without more specific information from you about your problem though.

Edit 2
regarding your comments:

I would like the app to be platform independent.

Well, Robot comes to mind then. You might want to have a sit-down with your client to find out what they dislike so much about Robot, and then gently explain that it might offer the best path towards a platform-independent solution.

Are there examples for JNA and/or JNI? I'm not familiar with either.

Yes there are lots of examples on this and other sites, and Google will help you find out more. JNA is a bit easier to work with as it doesn't require you to create a C bridge program, but it can be a little slower than JNI, and doesn't work directly with C++ code (as far as I know).

Edit 3 regarding your comments:

I have a serial port listener (java app). I need to provide its contents onto a web browser. Clipboard seemed to be a way to do it.

And this is why it's so important for you to provide the context of your problem rather than what you think your code solution should be.

Communicating between applications is not an easy thing to do, and often Java is not the best tool for this since as it is designed to be as platform agnostic as possible, it does not provide tools that allow for easy integration with low-level OS functions. I don't know the best way to solve your problem, but my intuition tells me that using clipboard may not be the way to go. Much may depend on which web browser you're talking about, whether it has some sort of API that allows for interface with other programs, things I know little about. Also where is your program sitting? On the user's computer? Have you considered using a Java web browser library of some type, creating your own specialized web browser program, and obtaining the data directly from your serial port listener (again, I have not done this myself, but have seen it described on SO)?

I don't understand how bridging to a C program will help me.

I'm not suggesting this. This would only be needed if you used JNI, something I avoid since JNA is much easier (at least for me).