I was following the tutorial that came in the Eclipse editor (click Help -> Welcome -> Tutorials). I worked through all the steps which were:
This cheat sheet shows you how to create a “Hello World” application
that uses the Standard Widget Toolkit (SWT). The application will
simply display an empty window to the user. If you need help at any
step, click the (?) to the right. Let’s get started!If you’re not already in the Java perspective, in the main menu select
Window > Open Perspective > Java or click on the “Click to Perform”
link below.Open the Import wizard from the main menu via File > Import…, and
select Plug-in Development > Plug-ins and Fragments. Click Next. On
the Import Plug-ins and Fragments page, select Import from: The
active target platform. Plug-ins and Fragments to import: Select from
all plug-ins and fragments found at specified location. Import As:
Projects with source folders. Click Next. On the Selection page, Add
org.eclipse.swt.{platform}.{os}.{arch} (for example:
org.eclipse.swt.win32.win32.x86 for win32) to Plug-ins and Fragments
to Import: list. Click Finish. This will create the
org.eclipse.swt.{platform}.{os}.{arch} project which we will need to
compile and run the application.Now we need a project to store our own source code. In the main
toolbar, click on the New Java Project button, or click on the link
below. Enter HelloWorldSWT for the project name, then click Finish.Since our project requires SWT, we need to specify this in the project
properties. Right-click on the project and select Properties. In the
Java Build Path page open the Projects tab, add the
org.eclipse.swt.{platform}.{os}.{arch} project, then click OK.The next step is to create a new class. In the main toolbar, click on
the New Java Class button (or the link below). If not already
specified, select HelloWorldSWT/src as the source folder. Enter
HelloWorldSWT for the class name and select the checkbox to create the
main() method, then click Finish. The Java editor will automatically
open showing your new class.In the Java editor, enter the following Java code in the main()
method: Display display = new Display(); Shell shell = new
Shell(display); shell.setText(“Hello world!”); shell.open(); while
(!shell.isDisposed()) { if (!display.readAndDispatch())
display.sleep(); } display.dispose(); You will get compile errors.
Right click in the Java editor and select Source > Organize Imports,
then save your changes.To run your application, right-click on your class in the Package
Explorer and select Run As > Java Application. A new empty window
should appear with the title “Hello world!”. Congratulations! You have
successfully created a Hello World SWT application!
And here’s a screenshot:

But when I tried to run the program, instead of displaying a blank screen as expected, it dumped this in the terminal:
Exception in thread "main" java.lang.UnsatisfiedLinkError: Could not load SWT library. Reasons:
no swt-cocoa-4233 in java.library.path
no swt-cocoa in java.library.path
Can't load library: /Users/devenkelling/.swt/lib/macosx/x86_64/libswt-cocoa-4233.jnilib
Can't load library: /Users/devenkelling/.swt/lib/macosx/x86_64/libswt-cocoa.jnilib
at org.eclipse.swt.internal.Library.loadLibrary(Library.java:331)
at org.eclipse.swt.internal.Library.loadLibrary(Library.java:240)
at org.eclipse.swt.internal.C.<clinit>(C.java:21)
at org.eclipse.swt.widgets.Display.<clinit>(Display.java:101)
at HelloWorldSWT.main(HelloWorldSWT.java:11
I’m using an x64 system with the 64-bit Eclipse installed and both 32-bit and 64-bit versions of Java (I think). Please help. Thanks.
This worked for me:
Right-click on your your project folder
HelloWorldSWT;Go to
Properties-> Left SidebarJava Build Path-> TabProjects;Expand the
org.eclipse.swt.cocoa.macosx.x86_64folder by clicking on the arrow left to it;Select
Native library locationand clickEdit;Click the
Workspacebutton and selectorg.eclipse.swt.cocoa.macosx.x86_64;Click
OKa couple of times;And you’re done! Hope this helped.