reference « PropertyFile « Java I/O Q&A

1. Java .properties file, how to reference already defined property later, dir.default=/home/data/in/

## define a default directory for Input files  

dir.proj1=dir.default /p1  
dir.proj2=dir.default /p2  
dir.proj3=dir.default /p3  
is this possible?

2. Can I reference another property in a properties file (use ${property})

look at my "":

key1= My name is
key2= ${key1} Martin !

Why when I get the value of "key2" my result is "${key1} Martin !" unlike "My name is Martin !" => ...

3. How to reference a system property within a user-defined .properties file?

I want to define a property for a working directory(say work.dir=/home/username/working-directory), for my production .properties file, without hard-coding the /home/username.I want to reference the system property user.home in place on the ...

4. Can java properties file reference other properties file?

Can java properties file reference other properties file?