Current Limitations and Disadvantages of Java

These exist mostly because the language is still evolving.

It is unclear which problems will be solved and when.

1. Slow

   • Internet as a whole

     • Potential huge show-stopper problem.

     • Bandwidth is a limited resource that is easily squandered.

     • Minimal incentive for people to conserve.

     • Potential demand is unbounded, potential supply is bounded.

     Solutions:

     • Write applications instead of applets (but then you lose some advantages)

     • Cache your applets (only partial solution).

     • Be a good Internet citizen: Minimize your use of detailed images and other bandwidth-hungry objects

   • Java compiler

     • Not yet well optimized.

     • Takes more time to compile a large program than a good C++ compiler.

   • Java programs

     • Byte-code interpretation is slow

       - 20-50 times slower than C++

     • Other factors:
       • Much run-time error checking done

       • Memory management is somewhat expensive

     • Partial solution: Get a real (non bytecode) compiler - coming later this year
       • Asymmetrix SuperCede - probably fastest

       • Borland Latte

       • Symantec Café

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2. Environment limitations

   Currently lacks:

   • Browser

     - This might be the biggest weakness, although there is promise on the horizon

   • Interactive source-level debugger

   • User interface builder

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3. Applet limitations imposed due to security model

   • Cannot access local data

   • Can only download data from the site where the applet is located

   • Cannot make system calls

   • Solution: Use applications

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4. Uncertain status of security

   • Security `holes' are repeatedly found.

   • Unclear when problem will stop

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5. Programming language limitations

   • No `Templates' yet.
     • Limits ability to create really good data structures

   • No `Function pointers' or `blocks'
     • These would allow greater abstraction and more flexible data-structure design

     • Available in both C++ and Smalltalk

   • Basic classes in class library are lacking important features
     • The class library was created to quickly and has now been widely adopted, making it hard to change.

     • This is also a problem with other languages

     • We can expect the current widespread standardization to fragment as vendors introduce competing classes to fill the gaps

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6. Platform limitations

   Full environment available only for:

   • Windows 95/NT

   • Macintosh

   • Sun Solaris

   Other platforms must wait for 3rd party support

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7. General stability concerns

   There are many bugs in:

   • Browsers

   • Example programs

   Change is very rapid