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Editorial Team
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Asked: 2026-05-13T19:11:14+00:00

When debugging some web-service client code today (in Java, with jax-ws) I ran across

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When debugging some web-service client code today (in Java, with jax-ws) I ran across a web-service method with the mind-blowing amount of 97 parameters!

I had to create a test case that calls this method, and I noticed several things:

  • code assist/hover doesn’t scale well. I am using Eclipse, and the tooltip over the method is as wide as the screen and spans several lines.
  • I had to copy parameters values from a previous xml capture, and it was practically impossible to remember “where am I” – when I had the cursor located after a comma and before typing some value, I often got the data type wrong – I typed an Integer instead of a String and vice versa.
  • Even after I wrote all the parameters, I still had some errors and the signature didn’t match. Unfortunately Eclipse marks the whole line in red as having an error, so finding where the mistake was took even more time 🙁

So this got me thinking, what do you think is the maximum sane number of parameters for a method? And if you could change this web-service signature, how do you think it can be improved?

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1 Answer

  1. Editorial Team

    There is no clear limit, but I am uncomfortable with more than 3-4 parameters. AFAIR Uncle Bob Martin in Clean Code recommends max 3.

    There are several refactorings to reduce the number of method parameters (see Working Effectively with Legacy Code, by Michael Feathers for details). These come to my mind:

    • encapsulate many related parameters into a single object (e.g. instead of String surName, String firstName, String streetAddress, String phoneNumber pass a Person object containing these as fields)
    • pass parameters in the constructor or other method calls prior to the invocation of this method
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