How to overwrite one property in .properties without overwriting the whole file?

Question

Basically, I have to overwrite a certain property in a .properties file through a Java app, but when I use Properties.setProperty() and Properties.Store() it overwrites the

Answer 1

You can use PropertiesConfiguration from Apache Commons Configuration.

In version 1.X:

PropertiesConfiguration config = new PropertiesConfiguration("file.properties");
config.setProperty("somekey", "somevalue");
config.save();

From version 2.0:

Parameters params = new Parameters();
FileBasedConfigurationBuilder builder =
    new FileBasedConfigurationBuilder(PropertiesConfiguration.class)
    .configure(params.properties()
        .setFileName("file.properties"));
Configuration config = builder.getConfiguration();
config.setProperty("somekey", "somevalue");
builder.save();