Java : getResourceAsStream in static method

To call getResourceAsStream in a static method, we use ClassName.class instead of getClass()

1. In non static method

	getClass().getClassLoader().getResourceAsStream("config.properties"))

2. In static method

	ClassName.class.class.getClassLoader().getResourceAsStream("config.properties")) 

1. Non Static Method

A .properties file in project classpath.

#config file
json.filepath = /Users/mkyong/Documents/workspace/SnakeCrawler/data/

package com.mkyong;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class FileHelper {

    public static void main(String[] args) {

        FileHelper obj = new FileHelper();
        System.out.println(obj.getFilePathToSave());

    }

    public String getFilePathToSave() {

        Properties prop = new Properties();

        String result = "";

        try (InputStream inputStream = getClass()
				.getClassLoader().getResourceAsStream("config.properties")) {
			
            prop.load(inputStream);
            result = prop.getProperty("json.filepath");

        } catch (IOException e) {
            e.printStackTrace();
        }

        return result;

    }

}

Output

/Users/mkyong/Documents/workspace/SnakeCrawler/data/

2. Static Method

If the method getFilePathToSave() is converted into a static method, the getClass() method will be failed, and prompts Cannot make a static reference to the non-static method getClass() from the type Object

To fix this, update getClass() to ClassName.class

package com.mkyong;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class FileHelper {

    public static void main(String[] args) {

        System.out.println(getFilePathToSaveStatic());
    }    

    public static String getFilePathToSaveStatic() {

        Properties prop = new Properties();

        String result = "";

        try (InputStream inputStream = FileHelper.class
				.getClassLoader().getResourceAsStream("config.properties")) {
				
            prop.load(inputStream);
            result = prop.getProperty("json.filepath");

        } catch (IOException e) {
            e.printStackTrace();
        }

        return result;

    }

}

Output

/Users/mkyong/Documents/workspace/SnakeCrawler/data/

References

• Java Properties file examples
• ClassLoader JavaDocs