Why is the EVAL command not able to execute when I pass a java string with variables in it?

Why is the EVAL command not able to execute when I pass a java string with variables in it?

The following code does not work properly

clear foo

   jstr=java.lang.String('foo=3;'); % create java string

   eval(jstr)                       % evaluate foo in this (caller) workspace

   who foo

The following code generates an error

   foo=3;

   jstr=java.lang.String('foo*2');

   bar=eval(jstr);                  % BUG!! foo exists but is not found

 ??? Undefined function or variable 'foo'.

 Error in ==> D:\MATLAB6p1\toolbox\matlab\lang\@opaque\eval.m

 On line 18  ==>     varargout{1:nargout} = eval(tryVal);

Answer 1

[MathWorks Support Team]

This is a bug in MATLAB when using the EVAL function with a java string with variables. Our development staff is currently investigating this issue.

As a workaround, you can convert the Java String to a MATLAB Character array before calling the EVAL function. For example:

clear foo

   jstr=java.lang.String('foo=3;');

   eval(char(jstr))

   who foo