What's in an Eclipse .Classpath/.Project File

How is .classpath file in eclipse generated?

The .classpath file reflects the content of all the settings that you apply manually to your BUILD PATH setup within your project.

In other words: while using the eclipse UI to setup the BUILD PATH, all that information goes into the .classpath file.

And it is perfectly possible to stop eclipse and make changes to that file within your preferred editor; then restart eclipse, probably do a full refresh; and (unless you messed up) the changes should be visible when opening your BUILD PATH settings again.

Interpreting eclipse .classpath file. What does 'kind=con' and 'exported=true' mean?

1) In kind="con", the con stands for container, which is interpreted by eclipse as a classpath container. As described in that link:

A classpath container provides a way to indirectly reference a set of
classpath entries through a classpath entry of kind CPE_CONTAINER

In other words, it enables grouping of other classpath entries in any way and re-use it wherever (including the ability of having different entries for different projects).

2) exported:
Say you have Project B that depends on Project C. The dependency is defined as exported=true. Then, another Project A that depends on Project B, will have also Project C present on A'a classpath.

How to place a file on classpath in Eclipse?

One option is to place your properties file in the src/ directory of your project. This will copy it to the "classes" (along with your .class files) at build time. I often do this for web projects.

.classpath file in Java related to Java or Eclipse

.class files are related to Java.

You write your code in java, it is compiled by javac into bytecode. The bytecode is stored in the .class files, and further interpreted by the Java virtual machine (JVM).

About .classpath on Wikipedia:

Similar to the classic dynamic loading behavior, when executing Java programs, the Java Virtual Machine finds and loads classes lazily (it loads the bytecode of a class only when this class is first used). The .classpath tells Java where to look in the file-system for files defining these classes.

So the .classpath mechanism is related to Java, and is handled by eclipse thanks to the .classpath file.

Hope it helps :)

Working with Eclipse .classpath and project files in Git?

You should put the .classpath file in .gitignore so that it never enters git in the first place.

This way, each developer will have a purely local copy.

To manage your dependencies, you should use Maven; its pom.xml is machine-independent and can live in git, and Eclipse can generate everything else from that file.

Where would I find and how would I fix my .classpath file

Each Java Project in the workspace has a .classpath file. Things like the Package Explorer do not normally show you this file because you can make most changes to it using the 'Java Build Path' page of the Project Properties.

Note: On macOS and Linux files with names starting with '.' are considered hidden and are not normally shown.

You can configure Package Explorer to show these files by clicking the View Menu (the small triangle at the top right of the view). Choose 'Filters...' and turn off the '.* resources' files.