CODEWITHSUNDEEP
javaeclipsedynamic-execution
student1234
student1234

Reputation: 201

Cannot find the file to dynamically execute it

I am using dynamic execution but it tells me that the class is not found although I double checked the path and it's correct

This is the method I am using

public static void runIt(String fileToCompile) throws ClassNotFoundException, IllegalArgumentException, IllegalAccessException, InvocationTargetException, InstantiationException, SecurityException, NoSuchMethodException
        {System.out.println("Entered runIt()");
            String r2="";
File file=File("/Users/apple/Documents/Documents/workspace/UserTesting/src/two.java");
            System.out.println("The path of the file is "+fileToCompile);
            System.out.println("HERE 1");
            try
            {
                // Convert File to a URL
                URL url = file.toURL(); // file:/classes/demo
                URL[] urls = new URL[] { url };
                System.out.println("HERE 2");
                // Create a new class loader with the directory
                ClassLoader loader = new URLClassLoader(urls);
                System.out.println("HERE 3");
                System.out.println("HERE 4");
                Class<?> thisClass=null;
                try{
                thisClass = classLoader.loadClass("two");
                }
                catch(ClassNotFoundException e){
                    System.out.println("Class not found");
                }
                System.out.println("HERE 5");
                Object newClassAInstance = thisClass.newInstance();
                System.out.println("HERE 6");
                
                Class params[] = new Class[1];
                params[0]=String[].class;
                Object paramsObj[] = {};
                String m=null;
                Object instance = thisClass.newInstance();
                System.out.println("HERE 7");
                Method thisMethod = thisClass.getDeclaredMethod("main", params);
                System.out.println("HERE 8");
                String methodParameter = "a quick brown fox";
                // run the testAdd() method on the instance:
                System.out.println((String)thisMethod.invoke(instance,(Object)m));
               
                                  
            }
            catch (MalformedURLException e)
            {
            }
            
        }

This prints

HERE 1

HERE 2

HERE 3

HERE 4

Class not found

HERE 5

Is there anything missing in the method

Upvotes: 0

Views: 73

Answers (2)

Random42
Random42

Reputation: 9159

You load a .java file by trying to load a class. First you must compile your .java into a .class and only then load it. You can compile .java file dynamically via the Java Compiler API.

If you already have the source at compile time (you do not generate at run-time the content of two.java) you should call Class.forName("two"); instead of classLoader.loadClass("two").

Upvotes: 0

ajay.patel
ajay.patel

Reputation: 1967

You are passing .java file, read about the class loaders , it is used for loading classes not java files. First compile the class, than try loading it.(Once compiled you dont have to pass path as

/Users/apple/Documents/Documents/workspace/UserTesting/src/two.class

rather pass

/Users/apple/Documents/Documents/workspace/UserTesting/src/

This should work.(assuming your class in compiled and present in above mentioned dir)

Upvotes: 0

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