[1] pry(main)> class NormalClass
[1] pry(main)*   java_signature "java.lang.String hello"
[1] pry(main)*   def self.hello
[1] pry(main)*     return 'hi'
[1] pry(main)*   end  
[1] pry(main)* end  
=> nil
[2] pry(main)> require 'jruby/core_ext'
=> true   
[4] pry(main)> NormalClass.become_java!.declared_methods
=> java.lang.reflect.Method[public static void rubyobj.NormalClass.clinit(org.jruby.Ruby,org.jruby.RubyClass), public static org.jruby.runtime.builtin.IRubyObject rubyobj.NormalClass.hello()]@55634720
[5] pry(main)> 

[7] pry(main)> class Foo
[7] pry(main)*   class << self
[7] pry(main)*     java_signature 'java.lang.String hello'
[7] pry(main)*     def hello()
[7] pry(main)*       return 'ohai'
[7] pry(main)*     end  
[7] pry(main)*   end  
[7] pry(main)* end  
Java::OrgJrubyParser::ParserSyntaxException: syntax error, unexpected end-of-file
from java.lang.reflect.Method.invoke(java/lang/reflect/Method.java:497)
[8] pry(main)> 
➜  ~  pry
[1] pry(main)> class Foo
[1] pry(main)*   class << self
[1] pry(main)*     java_signature 'java.lang.String hello'
[1] pry(main)*     def hello()
[1] pry(main)*       return 'lol'
[1] pry(main)*     end  
[1] pry(main)*   end  
[1] pry(main)* end  
=> nil
[2] pry(main)> require 'jruby/core_ext'
=> true
[3] pry(main)> Foo.become_java!.declared_methods
=> java.lang.reflect.Method[public static void rubyobj.Foo.clinit(org.jruby.Ruby,org.jruby.RubyClass), public static org.jruby.runtime.builtin.IRubyObject rubyobj.Foo.hello()]@26e356f0
[4] pry(main)>