How to find out if an installed Eclipse is 32 or 64 bit version?

How can I find out if a specific Eclipse instance on my (Windows 7) PC is the 32-bit or 64-bit version?

I've checked the About screen and the maze of dialogs one can call from there, but I didn't find any clues.

Also, right-clicking eclipse.exe in Windows explorer and opening the properties dialog box didn't give any hints.

Hit Ctrl+Alt+Del to open the Windows Task manager and switch to the processes tab.

32-bit programs should be marked with *32.

Open eclipse.ini in the installation directory, and observe the line with text:

plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.0.200.v20090519 then it is 64 bit.

If it would be plugins/org.eclipse.equinox.launcher.win32.win32.x86_32_1.0.200.v20090519 then it is 32 bit.

Help -> About Eclipse -> Installation Details -> tab Configuration

Look for -arch, and below it you'll see either x86_64 (meaning 64bit) or x86 (meaning 32bit).

In Linux, run file on the Eclipse executable, like this:

$ file /usr/bin/eclipse
eclipse: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.4.0, not stripped

Go to the Eclipse base folder → open eclipse.ini → you will find the below line at line no 4:

plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.200.v20150204-1316 plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.200.v20120913-144807

As you can see, line 1 is of 64-bit Eclipse. It contains x86_64 and line 2 is of 32-bit Eclipse. It contains x_86.

For 32-bit Eclipse only x86 will be present and for 64-bit Eclipse x86_64 will be present.