ninja-core/src/main/java/ninja/NinjaDefault.java
private final String readNinjaVersion() {
        
        // location of the properties file
        String LOCATION_OF_NINJA_BUILTIN_PROPERTIES = "ninja/ninja-builtin.properties";
        // and the key inside the properties file.
        String NINJA_VERSION_PROPERTY_KEY = "ninja.version";
        
        String ninjaVersion;
        try (InputStream stream = Thread.currentThread().getContextClassLoader().getResourceAsStream(LOCATION_OF_NINJA_BUILTIN_PROPERTIES)){

            Properties prop = new Properties();
            prop.load(stream);
            
            ninjaVersion = prop.getProperty(NINJA_VERSION_PROPERTY_KEY);
        
        } catch (Exception e) {
            //this should not happen. Never.
            throw new RuntimeErrorException(new Error("Something is wrong with your build. Cannot find resource " + LOCATION_OF_NINJA_BUILTIN_PROPERTIES));
        }
        
        return ninjaVersion;
        
    }
private final String readNinjaVersion() {
        
        // location of the properties file
        String LOCATION_OF_NINJA_BUILTIN_PROPERTIES = "ninja/ninja-builtin.properties";
        // and the key inside the properties file.
        String NINJA_VERSION_PROPERTY_KEY = "ninja.version";
        
        String ninjaVersion;
        try (InputStream stream = Thread.currentThread().getContextClassLoader().getResourceAsStream(LOCATION_OF_NINJA_BUILTIN_PROPERTIES)){

            Properties prop = new Properties();
            prop.load(stream);
            
            ninjaVersion = prop.getProperty(NINJA_VERSION_PROPERTY_KEY);
        
        } catch (Exception e) {
            //this should not happen. Never.
            throw new RuntimeErrorException(new Error("Something is wrong with your build. Cannot find resource " + LOCATION_OF_NINJA_BUILTIN_PROPERTIES));
        }
        
        return ninjaVersion;
        
    }
Simply reads a property resource file that contains the version of this
Ninja build. Helps to identify the Ninja version currently running.

@return The version of Ninja. Eg. "1.6-SNAPSHOT" while developing of "1.6" when released.