How to set a system property using a property file?

Question:

How to set a system property using a property file?

Code:

import java.io.FileInputStream;
import java.util.Properties;
 
public class PropertiesTest {
  public static void main(String[] args) throws Exception {
 
    // set up new properties object
    FileInputStream propFile = new FileInputStream( "myProperties.txt");
 
    Properties p = new Properties();
    p.load(propFile);
 
    // set the java properties
    System.setProperties(p);
 
    // display the properties
    System.getProperties().list(System.out);
  }
}

Output:

$ cat myProperties.txt
mprop=some prop
some.number=12345
com.foo.bla=abcdefg1234567


$ java PropertiesTest
-- listing properties --
some.number=12345
com.foo.bla=abcdefg1234567
mprop=some prop