java classes with non-public constructors are incorrectly instantiated

Details

  • Type: Bug Bug
  • Status: Closed Closed
  • Priority: Major Major
  • Resolution: Fixed
  • Affects Version/s: JRuby 1.1.4
  • Fix Version/s: JRuby 1.2
  • Component/s: Java Integration
  • Labels:
    None
  • Environment:
    JDK5 on MacOS X
  • Testcase included:
    yes

Description

I have a class:

package com.some.pkg;

public class Foo {
  boolean bar;

  Foo() {
      bar = true;
  }
}
$ jirb
irb(main):001:0> require 'dist/some-pkg.jar'
=> true
irb(main):002:0> x = com.some.pkg.Foo.new
=> #<Java::ComSomePkg::Foo:0x1be20c @java_object=java.lang.Object@2342ed>
irb(main):003:0> x.class
=> Java::ComSomePkg::Foo
irb(main):004:0> x.inspect
=> "#<Java::ComSomePkg::Foo:0x1be20c @java_object=java.lang.Object@2342ed>"

As you can see above, the internal @java_object is of a type Object, instead of com.some.pkg.Foo. This means that even though JRuby returned some object when I called Foo.new, this object is not a valid instance of com.some.pkg.Foo class.

This also results in odd errors when I call methods of the corrupted instance:

irb(main):006:0> x.bar    
TypeError: invokee not instance of method's class (gotjava.lang.Object wanted com.some.pkg.Foo)
	from (irb):7:in `binding'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:150:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:259:in `signal_status'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:147:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:146:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:70:in `start'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `catch'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `start'
	from /usr/local/jruby/current/bin/jirb:19
irb(main):007:0> x.getBar
TypeError: invokee not instance of method's class (gotjava.lang.Object wanted com.some.pkg.Foo)
	from (irb):8:in `binding'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:150:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:259:in `signal_status'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:147:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:146:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:70:in `start'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `catch'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `start'
	from /usr/local/jruby/current/bin/jirb:19
irb(main):005:0> x.get_bar
TypeError: invokee not instance of method's class (gotjava.lang.Object wanted com.some.pkg.Foo)
	from (irb):6:in `binding'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:150:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:259:in `signal_status'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:147:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:146:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:70:in `start'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `catch'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `start'
	from /usr/local/jruby/current/bin/jirb:19

Another problem that might or might not be related is that when a class with a non-public constructor with parameters is created which suppresses the implicit parameterless constructor, JRuby tries to instantiate this class using the parameterless constructor:

package com.some.pkg;

public class Foo {
  boolean bar;

  Foo(boolean requiredParam) {
    bar = requiredParam;
  }

  public boolean getBar() {
      return bar;
  }
}
$ jirb
require 'irb(main):001:0> require 'dist/some-pkg.jar'
=> true
irb(main):002:0> x = com.some.pkg.Foo.new(true)
ArgumentError: wrong # of arguments(1 for 0)
	from (irb):4:in `binding'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:150:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:259:in `signal_status'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:147:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:146:in `eval_input'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:70:in `start'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `catch'
	from /usr/local/jruby/jruby-1.1.4/lib/ruby/1.8/irb.rb:69:in `start'
	from /usr/local/jruby/current/bin/jirb:19
irb(main):003:0> x = com.some.pkg.Foo.new
=> #<Java::ComSomePkg::Foo:0x1be20c @java_object=java.lang.Object@2342ed>

I'm not entirely sure if JRuby can instantiate classes via non-public constructors, if that was not possible, an exception should be raised instead of returning corrupted objects.

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Charles Oliver Nutter added a comment -

Ok, so here's the deal. The example you gave is actually a package-visible constructor, which can't be called unless the subclass is also in the same package. We don't do that because it can often break cases where the original package has been signed, and it's hard to detect that. So I did not modify the behavior that causes constructing through a package-visible constructor to fail. What I did do, however, was make the error message actually reflect the original Java exception's error message, which should generally be enough to indicate that the method is not visible.

Public and protected superclass constructors should do work fine. I added specs for public/protected working and private/package failing. All committed in r9079.

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Charles Oliver Nutter added a comment - Ok, so here's the deal. The example you gave is actually a package-visible constructor, which can't be called unless the subclass is also in the same package. We don't do that because it can often break cases where the original package has been signed, and it's hard to detect that. So I did not modify the behavior that causes constructing through a package-visible constructor to fail. What I did do, however, was make the error message actually reflect the original Java exception's error message, which should generally be enough to indicate that the method is not visible. Public and protected superclass constructors should do work fine. I added specs for public/protected working and private/package failing. All committed in r9079.
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Igor Minar added a comment -

ok, I understand. Thanks!

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Igor Minar added a comment - ok, I understand. Thanks!

People

  • Assignee:
    Charles Oliver Nutter
    Reporter:
    Igor Minar
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Dates

  • Created:
    Updated:
    Resolved: