Android Question PARSE ERROR: unsupported class file version 53.0

[kkkpe]

I try to include a jar file but it returns this error:
PARSE ERROR: unsupported class file version 53.0

 

[drgottjr]

may i ask exactly what you thought the jar was supposed to do?

 

[kkkpe]

it's just one of the libraries that will need to be added to the project ..
but already doing a test with only it returns an error

 

[drgottjr]

it's not java. and it's not really a library. have you looked at it? i repeat my question: what did you think it was going to do? it's basically a webpage, but a java tool was used to archive it. but when b4a's compiler opens it to compile your project, there's nothing there to compile (the "class" is empty). you'd have better luck un-zipping it. just saying you needed to add it to the project doesn't say much.

 

[kkkpe]

this is the class in java and I compiled it with BlueJ

 

[drgottjr]

ziwiIntegrator.java is java. how you got to ziwiIntegrator.jar, only god knows. maybe you'd have something usable if you pass ziwiIntegrator.java to erel's simple library compiler. not familiar with bluej, so i don't know which button to push.

UPDATE:
doesn't build with simple library compiler, sorry. it uses a higher level of java than supported by slc. in theory, it's possible to turn lambda expressions into non-lambda, but i didn't count them or any other issues. you'll have to find out how to use bluej to create a valid jar. what you got is probably some kind of javadoc instructions, but there is no actual java code that can be included in your project.

 

[drgottjr]

this may be of no help to you, and i apologize for that.

bluej made no sense to me. it seemed quite happy to build
an empty.jar, not unlike the one you built with it. plus, according
to SO, bluej is not designed to be used for android. whatever.

i took ziwiIntegrator.java and modified it so that it builds with erel's
simple library compiler. it was moderately tedius; a number of small
changes relating to the version of java needed for slc were required.
(lambda expressions and the diamond operator cannot be handled,
but it's not difficult to change them.) there was also 1 important
change, which didn't quite make sense to me regarding the alertdialog (i am
familiar with building alertdialogs which is why the change felt strange).
if i were expecting a problem when trying to include the library, i think
it would be at that point.)

wherever the compiler stopped with an error, i made the error go away.
you now have a ziwiIntegrator.jar which you can add to your additional
libraries folder and include in your project. what happens when you
access it, i cannot say as i didn't spend all the time necessary to learn
what the library is supposed to do.

i am returning to you the modified ziwiIntegrator.java file. anyone who
feels so inclined can use it (or revert to the original). the modified file
will compile with the simple library compiler, so that might be a
convienient place to start in the event my changes cause a problem.
(it would be a simple matter to compare the original against my changes.)

i have no idea how it is incorporated into your project, so i had no way to
test it.

 

[Erel]

unsupported class file version 53.0

This means that it was compiled with the target set to Java 9. You need to change it to Java 7 or 8. With 8 you might need to desugar it.

 

[kkkpe]

Now I'm trying to use Erel's SLC compiler, but it immediately returns error: error: package android.app does not exist
import android.app.Activity;
How to do?