[Bug]: Bindgen tool generates incorrect code

[hasithaa]

Description

Bindgen tool generates a code with compilation errors.

Steps to Reproduce

1. Create a project
2. Inside the project execute bal bindgen -mvn com.github.jknack:handlebars:4.3.1 --public com.github.jknack.handlebars.Handlebars com.github.jknack.handlebars.Template
3. Compiler the project.

Compiling source
        hasitha/test:0.1.0
ERROR [modules/com.github.jknack.handlebars/Template.bal:(41:20,41:46)] incompatible types: expected '(string|hasitha/test.java.io:0.1.0:IOException)', found 'string?'
ERROR [modules/com.github.jknack.handlebars/Template.bal:(68:20,68:46)] incompatible types: expected '(string|hasitha/test.java.io:0.1.0:IOException)', found 'string?'
error: compilation contains errors

Affected Version(s)

Update9 RC1

OS, DB, other environment details and versions

No response

Related area

-> Bindgen Tool

Related issue(s) (optional)

No response

Suggested label(s) (optional)

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Suggested assignee(s) (optional)

No response

[keizer619]

This is happening in 2201.8.6 as well

[NipunaRanasinghe]

@hasithaa @keizer619 Ack. I'll look into this and, will update with the progress.