core/src/main/java/org/jruby/RubyBasicObject.java
public IRubyObject instance_variable_get(ThreadContext context, IRubyObject name) {
        Object value = variableTableFetch(validateInstanceVariable(name));

        return value != null ? (IRubyObject) value : context.nil;
    }
/** rb_obj_ivar_get
     *
     *  call-seq:
     *     obj.instance_variable_get(symbol)    => obj
     *
     *  Returns the value of the given instance variable, or nil if the
     *  instance variable is not set. The <code>@</code> part of the
     *  variable name should be included for regular instance
     *  variables. Throws a <code>NameError</code> exception if the
     *  supplied symbol is not valid as an instance variable name.
     *
     *     class Fred
     *       def initialize(p1, p2)
     *         @a, @b = p1, p2
     *       end
     *     end
     *     fred = Fred.new('cat', 99)
     *     fred.instance_variable_get(:@a)    #=> "cat"
     *     fred.instance_variable_get("@b")   #=> 99
     */


Returns the value of the given instance variable, or nil if the
instance variable is not set. The @ part of the
variable name should be included for regular instance
variables. Throws a NameError exception if the
supplied symbol is not valid as an instance variable name.


Returns the value of the given instance variable or nil if the instance variable is not set . The @ part of the variable name should be included for regular instance variables . Throws a NameError exception if the supplied symbol is not valid as an instance variable name .
public IRubyObject instance_variable_get(ThreadContext context, IRubyObject name) {
        Object value = variableTableFetch(validateInstanceVariable(name));
        return value != null ? (IRubyObject) value : context.nil;
    }
public IRubyObject instance_variable_get ( ThreadContext context , IRubyObject name ) { Object value = variableTableFetch ( validateInstanceVariable ( name ) ) ; return value != null ? ( IRubyObject ) value : context . nil ; }
rb_obj_ivar_get
  call-seq:
     obj.instance_variable_get(symbol)    => obj
rb_obj_ivar_get call - seq : obj . instance_variable_get ( symbol ) = > obj