Dynamic runtime compilation with custom classes

[joanbonilla]

Hi,

I have a spring boot application with some custom code and I've tried to compile that sample with a custom class inside.

Can I compile dynamic classes with my custom code?

Expected behavior and actual behavior:

Expected: show the "Hello World!" message

Actual:

I get the next error (classloader):

Compilation error: /com/sample/soc/RuntimeCompilerTest.java:1: error: package com.sample.spring does not exist\r\npackage com.sample.soc; import com.sample.spring.WebsitesBO; class RuntimeCompilerTest implements java.util.function.Supplier { public String get() { return \"Hello World!\"; } }\r\n ^\r\n1 error\r\n

Steps to reproduce the problem:

Create package com.sample.spring and create Java class in this package named WebsitesBO

Copy the next code and run it:

Supplier<String> supplier = Reflect.compile(
            "com.sample.soc.RuntimeCompilerTest",
            "package com.sample.soc; " +
                    "import com.sample.spring.WebsitesBO; " +
                    "class RuntimeCompilerTest implements java.util.function.Supplier<String> { " +
                    "public String get() { " +
                    "return \"Hello World!\"; } " +
                    "}"
    ).create().get();

Versions:

• jOOR: 0.9.8 and 0.9.9
• Java: 8

Thank you

[lukaseder]

Thanks for your report and for creating the issue :)

It should definitely work (see also some tests here: https://github.com/jOOQ/jOOR/blob/master/jOOR/src/test/java/org/joor/test/CompileTest.java), but is the com.sample.spring package visible to the code that invokes the compile method?

[lukaseder]

Can you create a test case to help reproduce this?

[joanbonilla]

You can reproduce it with this repo: https://github.com/joanbonilla/dynamic-compiler

Run it with mvn spring-boot:run

[lukaseder]

I see, thanks for the test case. Very interesting. When I run the class in Eclipse, it works. It doesn't work from whatever the spring-boot:run goal is doing. This seems to be some sort of a class loader issue.

[lukaseder]

Does this issue fix it? https://github.com/jOOQ/jOOR/issues/65

[lukaseder]

Tried it myself. #65 doesn't seem to fix it

[joanbonilla]

I solved the issue with some tips in your library about the classloader, I needed to use the current Classloader

[joanbonilla]

Do you want the code I just implemented in a new branch?

[lukaseder]

Do you want the code I just implemented in a new branch?

Is that it? https://github.com/joanbonilla/jOOR/commit/34f2379c775c2b5caa6bc4218e6d26e5edb1ca1d

The solution would be something similar, but the ClassLoader reference would go into the CompileOptions argument type. That's why it was added - because I don't want to overload new methods every time a new compile option is being considered.

[joanbonilla]

Are you using CompileOptions as context pattern object?

[lukaseder]

I don't know what a "context pattern object" is

[joanbonilla]

I did another branch:

https://github.com/joanbonilla/jOOR/commit/2d97d14108a23617221cdfed93471951cd3be9ab

[lukaseder]

Thanks. I've had a look at this when taking an attempt at implementing #72. Your code will affect the JDK 8 distribution, but what about JDK 9+? How can we define a class on an existing class loader when we're no longer allowed to "open up" the ClassLoader.defineClass() method through reflection? Lookup can be used, but it is much more difficult to get right...