How do I read runtime variables inside java class?

Question

I have a java app that looks something like this

java -Dconfig.dir = ../../.. -jar blah..

how can I access this config.dir in java application at run time.I am trying to load a properties file that will be there at run time.So I want to load this in file stream

@Glains in this case this will not work as value for `config.dir` property is not passed as a parameter to the main method — Ivan, Oct 26 '18 at 15:34
@Praveen do not use spaces in java command line `-Dconfig.dir = ../../..` use it as `-Dconfig.dir=../../..` and then use @Ivan comment BTW: @Glains you are not right. — Vadim, Oct 26 '18 at 15:36
See also https://stackoverflow.com/questions/5045608/proper-usage-of-java-d-command-line-parameters — Andy Thomas, Oct 26 '18 at 16:08

score 0 · Accepted Answer · answered Oct 26 '18 at 15:43

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Ivan gave the correct answer in a comment.

System.getProperty("config.dir")

answered Oct 26 '18 at 15:43

Steve11235

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score 0 · Answer 2 · answered Oct 26 '18 at 15:43

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For your use case, you need to add the location of the properties file in the class path and then follow the steps given in this answer.

If you really want to read the -D parameter, refer to @Ivan comment

answered Oct 26 '18 at 15:43

Saptarshi Basu

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yeah cant have properties file inside project.Will foolow Ivan's comment – Praveen Oct 26 '18 at 15:50
@Praveen You don't need to have the properties file in project to be able to add the location in classpath. You can add any random director location to the classpath using the `-classpath` java command line switch – Saptarshi Basu Oct 26 '18 at 15:56
ooh I was not aware of that let me try that – Praveen Oct 26 '18 at 16:00

How do I read runtime variables inside java class?

2 Answers2