Checkstyle: How to Resolve "Hidden Field" Error

Question

I am getting this checkstyle error:

'serverURL' hides a field

in this

 private static void setServerURL(final String serverURL) {
    Utility.serverURL = serverURL;
 }

What could be the reason, and how to resolve it?

Cory Kendall · Answer 1 · 2015-01-27T23:34:51.057

63

There is already a variable defined serverURL which is available to this method (additional to the formal parameter you are accepting). This is called "shadowing".

I think most Java programmers turn this check off, because it's not really that confusing.

For example, this would trigger the error:

public class Foo {
  private int bar = 0;

  public void someMethod(int bar) {
    // There are two bars!  All references in this method will use the parameter bar,
    // unless they are explicitly prefixed with 'this'.
    this.bar = bar;
  }
}

edited Jan 27 '15 at 23:34

answered Oct 15 '11 at 05:46

Cory Kendall

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1

As you see method is static, i can not use this – Romi Oct 15 '11 at 06:10
7

@CoryKendall What do you propose is the solution to this problem? – IgorGanapolsky Feb 20 '14 at 16:58
1

The solution is to turn off the check, or chance the name of one of the `bar`s to something else. – Cory Kendall Nov 07 '16 at 20:34
2

This answer could be improved by specifying how to turn off that checkstyle. – wachr Jan 17 '18 at 19:31

score 53 · Answer 2 · answered Apr 26 '15 at 14:57

53

I think it is very common in constructors and setters that the set field name is the same as the setter parameter name. This is why i recommend this configuration:

<module name="HiddenField" >
    <property name="ignoreSetter" value="true" />
    <property name="ignoreConstructorParameter" value="true" />
</module>

This way the other hidden field cases are still forbidden.

answered Apr 26 '15 at 14:57

WonderCsabo

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5

still not working with above properties in my checkstyle xml file. – Gaurav May 21 '19 at 14:33

score 11 · Answer 3 · answered Oct 18 '12 at 10:17

The parameter and the static field have the same name. Just rename one of them. Some people follow a naming convention that prefixes all parameters with p. Then you would have serverURL as field name and pServerURL as parameter name. Or you could simply turn off the check.

score 7 · Answer 4 · answered Mar 18 '13 at 02:31

7

I resolved it by disabling it in eclipse. I was looking for how to do that when I landed on this page. I didn't find the answer in top 10 google query so I had to figure it out the hard way. For someone who is looking for that, here is how I did it:

Open

Eclipse>Preferences>Checkstyle

Find the checkstyle configuration you are using (you might have set that or your are using default in which case its a better idea to create a copy of your own and then edit that). Select that and then click the configure button on the right side. Find the following config in the list:

Coding Problems>Hidden Field

Open the configuration (there is button called 'open' in the UI).

Unselect 'Parameter Declaration'. Click OK then Click OK and then Click OK.

answered Mar 18 '13 at 02:31

T A

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For some reason my check style had multiple "hidden field" options under "Coding Problems". I disabled all of them then only enabled one and followed the directions above and it worked. Wanted to do a plug for clarification in case others have the same problem. – James Oravec Apr 11 '13 at 14:26
How about fixing the code than to turn of the checker? see Cory Kendall's answer – Hannes M Jul 05 '13 at 06:58
@Hannes Sure. That is exactly the solution **checkstyle** is suggesting to the user. However people landing on this page are looking for ways to make checkstyle stop warning for that. – T A Jul 07 '13 at 23:03

score 6 · Answer 5 · answered Apr 18 '14 at 23:19

6

Just change ur param name in ur method

private static void setServerURL(final String serverURL) {
Utility.serverURL = serverURL;
}

to

private static void setServerURL(final String serverURLXYZ) {
Utility.serverURL = serverURLXYZ;
}

Enjoy...

Jigar Patel

answered Apr 18 '14 at 23:19

user3550483

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ahhhhhhhhhhhhhh! – Tucker Jun 30 '21 at 03:22
This isn't a clean solution :) – th3an0maly Dec 01 '22 at 16:42

score 0 · Answer 6 · answered Jul 10 '19 at 19:42

0

Kinda dumb error, but here is the easy fix I put in my setters to fix it:

was:

public void setName(String name) {
  this.name = name;
}

updated:

public void setName(String val) {
  this.name = val;
}

answered Jul 10 '19 at 19:42

Forrest

2,968
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This isn't a clean solution :) – th3an0maly Dec 01 '22 at 16:42
@th3an0maly With the checkstyle restrictions, this is the simplest thing I could figure out. What is something cleaner that you suggest? – Forrest Dec 02 '22 at 14:00

ppuskar · Answer 7 · 2023-08-18T07:39:11.290

0

I read the documnetation :

https://checkstyle.sourceforge.io/apidocs/com/puppycrawl/tools/checkstyle/checks/coding/HiddenFieldCheck.html

Here is the solution:

<module name="HiddenField">
   <property name="tokens" value="VARIABLE_DEF"/>
 </module>

If already have a HiddentField tag, then add the tokens property.

I had a similar issue, with this fix everything works fine.

edited Aug 18 '23 at 07:39

answered Aug 17 '23 at 20:45

ppuskar

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Checkstyle: How to Resolve "Hidden Field" Error

7 Answers7