CODEWITHSUNDEEP
javaresourcesclassloader
ikhebgeenaccount
ikhebgeenaccount

Reputation: 373

getResourceAsStream() returning null for properties file

I try to load a file named config.properties in the package config.

My project setup

A snippet of my code in Main.java:

        //Read config.properties
        Properties properties = new Properties();
        System.out.println(Main.class.getClassLoader().getResource("config/config.properties").toString());
        InputStream propertiesFile = Main.class.getClassLoader().getResourceAsStream("config/config.properties");
        properties.load(propertiesFile);

This however gives me a NullPointerException. But when I load img/background/background.png I use: (from Panel.java)

background = new ImageIcon(this.getClass().getClassLoader().getResource("img/background/background.png")).getImage();

This works fine. I've read a lot of questions on stackoverflow already, but can't find a solution to my problem. I do not see the difference between the loading of the background image or the properties file, other than the fact that the properties file is loaded in a static context. But as far as I can see, this should work.

What am I forgetting?

EDIT: I just ran System.out.println(Main.class.getClassLoader().getResource("config/config.properties").toString());, which printed the correct path to config.properties.

Stacktrace: java.lang.NullPointerException at main.Main.startGame(Main.java:70) at main.gui.panel.MenuPanel$1.actionPerformed(MenuPanel.java:31) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$400(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue$4.run(Unknown Source) at java.awt.EventQueue$4.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)

Main.java - line 70:

int maxFPS = Integer.getInteger(properties.getProperty("FPS"));

config.properties:

FPS=45
fpsCap=1

Upvotes: 2

Views: 3259

Answers (2)

ikhebgeenaccount
ikhebgeenaccount

Reputation: 373

The problem wasn't with the getResourceAsStream("config/config.properties"), but with the way I read the properties. Property FPS is written as a String, to make this in an int I had to use Integer.parseInt(), instead of Integer.getInteger().

Upvotes: 1

jbarrueta
jbarrueta

Reputation: 5175

Try getting it from the current thread context loader:

    Properties properties = new Properties();

    ClassLoader loader = Thread.currentThread().getContextClassLoader();

    try (InputStream in = loader.getResourceAsStream("config/config.properties")) {
        properties.load(in);
    } catch (IOException e) {
        throw new IllegalStateException("Cannot start, properties not found.");
    }

This code compiles for JDK 7+, since it uses auto closeable, but can be translated to previous JDK version by moving the resource loader statement to be in in the try-catch clause.

Upvotes: 0

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