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IntelliJ IDEA underlines variables when using += in JAVA
2019 Community Moderator ElectionHow can I permanently enable line numbers in IntelliJ?Is Java “pass-by-reference” or “pass-by-value”?When to use LinkedList over ArrayList in Java?How do I generate random integers within a specific range in Java?What is the scope of variables in JavaScript?How to determine if variable is 'undefined' or 'null'?How do I convert a String to an int in Java?IntelliJ inspection gives “Cannot resolve symbol” but still compiles codeCreating a memory leak with JavaHow to see JavaDoc in IntelliJ IDEA?
Since the new update (2018.2) IntelliJ IDEA underlines variables, when they are "unnecessarily" reassigned - this includes, however, each use of "+=".
Is this a mistake in the IDE or am I getting it wrong?
Please see this basic method as an example. (It just adds a list of numbers.)
java variables intellij-idea underline
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
asked Aug 5 '18 at 18:29
fandangofandango
686
add a comment |
Since the new update (2018.2) IntelliJ IDEA underlines variables, when they are "unnecessarily" reassigned - this includes, however, each use of "+=".
Is this a mistake in the IDE or am I getting it wrong?
Please see this basic method as an example. (It just adds a list of numbers.)
java variables intellij-idea underline
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
asked Aug 5 '18 at 18:29
fandangofandango
686
I'm not sure, but if you use jdk 10 these underlings may suggest you that you can usevarinstead ofint.
– zlakad
Aug 5 '18 at 18:32
Thanks for the reply. I actually downgraded to jdk 8/1.8, because nobody could open my jar :)
– fandango
Aug 5 '18 at 18:34
1
Well, it is unnecessary reassignment in the sense that you could just use a stream to calculate it... But I don't see that you are doing anything unusual there.
– Andy Turner
Aug 5 '18 at 18:46
add a comment |
Since the new update (2018.2) IntelliJ IDEA underlines variables, when they are "unnecessarily" reassigned - this includes, however, each use of "+=".
Is this a mistake in the IDE or am I getting it wrong?
Please see this basic method as an example. (It just adds a list of numbers.)
java variables intellij-idea underline
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
asked Aug 5 '18 at 18:29
fandangofandango
686
Since the new update (2018.2) IntelliJ IDEA underlines variables, when they are "unnecessarily" reassigned - this includes, however, each use of "+=".
Is this a mistake in the IDE or am I getting it wrong?
Please see this basic method as an example. (It just adds a list of numbers.)
java variables intellij-idea underline
java variables intellij-idea underline
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
asked Aug 5 '18 at 18:29
fandangofandango
686
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
asked Aug 5 '18 at 18:29
fandangofandango
686
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
edited Aug 5 '18 at 19:50
CrazyCoder
278k50657664
278k50657664
asked Aug 5 '18 at 18:29
fandangofandango
686
asked Aug 5 '18 at 18:29
fandangofandango
686
asked Aug 5 '18 at 18:29
fandangofandango
686
686
I'm not sure, but if you use jdk 10 these underlings may suggest you that you can usevarinstead ofint.
– zlakad
Aug 5 '18 at 18:32
Thanks for the reply. I actually downgraded to jdk 8/1.8, because nobody could open my jar :)
– fandango
Aug 5 '18 at 18:34
1
Well, it is unnecessary reassignment in the sense that you could just use a stream to calculate it... But I don't see that you are doing anything unusual there.
– Andy Turner
Aug 5 '18 at 18:46
add a comment |
I'm not sure, but if you use jdk 10 these underlings may suggest you that you can usevarinstead ofint.
– zlakad
Aug 5 '18 at 18:32
Thanks for the reply. I actually downgraded to jdk 8/1.8, because nobody could open my jar :)
– fandango
Aug 5 '18 at 18:34
1
Well, it is unnecessary reassignment in the sense that you could just use a stream to calculate it... But I don't see that you are doing anything unusual there.
– Andy Turner
Aug 5 '18 at 18:46
I'm not sure, but if you use jdk 10 these underlings may suggest you that you can use
var instead of int.– zlakad
Aug 5 '18 at 18:32
I'm not sure, but if you use jdk 10 these underlings may suggest you that you can use
var instead of int.– zlakad
Aug 5 '18 at 18:32
Thanks for the reply. I actually downgraded to jdk 8/1.8, because nobody could open my jar :)
– fandango
Aug 5 '18 at 18:34
Thanks for the reply. I actually downgraded to jdk 8/1.8, because nobody could open my jar :)
– fandango
Aug 5 '18 at 18:34
1
1
Well, it is unnecessary reassignment in the sense that you could just use a stream to calculate it... But I don't see that you are doing anything unusual there.
– Andy Turner
Aug 5 '18 at 18:46
Well, it is unnecessary reassignment in the sense that you could just use a stream to calculate it... But I don't see that you are doing anything unusual there.
– Andy Turner
Aug 5 '18 at 18:46
add a comment |
1 Answer
1
active
oldest
votes
It's a new feature of IntelliJ IDEA 2018.2:
Underlining reassigned local variables and reassigned parameters
IntelliJ IDEA now underlines reassigned local variables and reassigned parameters, by default. The attributes for all the languages supporting this feature, which for now include Java and Groovy, can be changed in Preferences/Settings | Editor | Color Scheme | Language Defaults | Identifiers | Reassigned.
Why it may be useful?
If the variable/parameter is underlined, you know that you can't use it in lambda/anonymous class directly.
When reading a very long method code, if the parameter is not underlined, you know for sure that its value is not reassigned anywhere in this method and it contains exactly the same value that was passed to this method at any point.
Some code guidelines are against reassigned variables and you may want to avoid them where possible to keep the code clean and make it easier to read/debug.
Nowadays many developers prefer to avoid mutable state, and reassign variables only in rare cases when it is really necessary. We don't want to manually enforce immutability, we suppose that everything is immutable by default and want to bring additional attention to the cases when something is not. If you use final to mark non-mutable variables it means that you need to write more code for regular cases and less code in exceptional cases. (BTW in modern languages declaring immutable variables doesn't require writing additional code, but unfortunately not in Java).
Brian Goetz, Java Language Architect, also likes the way IntelliJ IDEA highlights reassigned variables (see his tweet).
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
1
It's basically whatfinalcan be used for (only not everybody uses it)
– ACV
Jan 29 at 15:32
add a comment |
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It's a new feature of IntelliJ IDEA 2018.2:
Underlining reassigned local variables and reassigned parameters
IntelliJ IDEA now underlines reassigned local variables and reassigned parameters, by default. The attributes for all the languages supporting this feature, which for now include Java and Groovy, can be changed in Preferences/Settings | Editor | Color Scheme | Language Defaults | Identifiers | Reassigned.
Why it may be useful?
If the variable/parameter is underlined, you know that you can't use it in lambda/anonymous class directly.
When reading a very long method code, if the parameter is not underlined, you know for sure that its value is not reassigned anywhere in this method and it contains exactly the same value that was passed to this method at any point.
Some code guidelines are against reassigned variables and you may want to avoid them where possible to keep the code clean and make it easier to read/debug.
Nowadays many developers prefer to avoid mutable state, and reassign variables only in rare cases when it is really necessary. We don't want to manually enforce immutability, we suppose that everything is immutable by default and want to bring additional attention to the cases when something is not. If you use final to mark non-mutable variables it means that you need to write more code for regular cases and less code in exceptional cases. (BTW in modern languages declaring immutable variables doesn't require writing additional code, but unfortunately not in Java).
Brian Goetz, Java Language Architect, also likes the way IntelliJ IDEA highlights reassigned variables (see his tweet).
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
1
It's basically whatfinalcan be used for (only not everybody uses it)
– ACV
Jan 29 at 15:32
add a comment |
It's a new feature of IntelliJ IDEA 2018.2:
Underlining reassigned local variables and reassigned parameters
IntelliJ IDEA now underlines reassigned local variables and reassigned parameters, by default. The attributes for all the languages supporting this feature, which for now include Java and Groovy, can be changed in Preferences/Settings | Editor | Color Scheme | Language Defaults | Identifiers | Reassigned.
Why it may be useful?
If the variable/parameter is underlined, you know that you can't use it in lambda/anonymous class directly.
When reading a very long method code, if the parameter is not underlined, you know for sure that its value is not reassigned anywhere in this method and it contains exactly the same value that was passed to this method at any point.
Some code guidelines are against reassigned variables and you may want to avoid them where possible to keep the code clean and make it easier to read/debug.
Nowadays many developers prefer to avoid mutable state, and reassign variables only in rare cases when it is really necessary. We don't want to manually enforce immutability, we suppose that everything is immutable by default and want to bring additional attention to the cases when something is not. If you use final to mark non-mutable variables it means that you need to write more code for regular cases and less code in exceptional cases. (BTW in modern languages declaring immutable variables doesn't require writing additional code, but unfortunately not in Java).
Brian Goetz, Java Language Architect, also likes the way IntelliJ IDEA highlights reassigned variables (see his tweet).
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
1
It's basically whatfinalcan be used for (only not everybody uses it)
– ACV
Jan 29 at 15:32
add a comment |
It's a new feature of IntelliJ IDEA 2018.2:
Underlining reassigned local variables and reassigned parameters
IntelliJ IDEA now underlines reassigned local variables and reassigned parameters, by default. The attributes for all the languages supporting this feature, which for now include Java and Groovy, can be changed in Preferences/Settings | Editor | Color Scheme | Language Defaults | Identifiers | Reassigned.
Why it may be useful?
If the variable/parameter is underlined, you know that you can't use it in lambda/anonymous class directly.
When reading a very long method code, if the parameter is not underlined, you know for sure that its value is not reassigned anywhere in this method and it contains exactly the same value that was passed to this method at any point.
Some code guidelines are against reassigned variables and you may want to avoid them where possible to keep the code clean and make it easier to read/debug.
Nowadays many developers prefer to avoid mutable state, and reassign variables only in rare cases when it is really necessary. We don't want to manually enforce immutability, we suppose that everything is immutable by default and want to bring additional attention to the cases when something is not. If you use final to mark non-mutable variables it means that you need to write more code for regular cases and less code in exceptional cases. (BTW in modern languages declaring immutable variables doesn't require writing additional code, but unfortunately not in Java).
Brian Goetz, Java Language Architect, also likes the way IntelliJ IDEA highlights reassigned variables (see his tweet).
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
It's a new feature of IntelliJ IDEA 2018.2:
Underlining reassigned local variables and reassigned parameters
IntelliJ IDEA now underlines reassigned local variables and reassigned parameters, by default. The attributes for all the languages supporting this feature, which for now include Java and Groovy, can be changed in Preferences/Settings | Editor | Color Scheme | Language Defaults | Identifiers | Reassigned.
Why it may be useful?
If the variable/parameter is underlined, you know that you can't use it in lambda/anonymous class directly.
When reading a very long method code, if the parameter is not underlined, you know for sure that its value is not reassigned anywhere in this method and it contains exactly the same value that was passed to this method at any point.
Some code guidelines are against reassigned variables and you may want to avoid them where possible to keep the code clean and make it easier to read/debug.
Nowadays many developers prefer to avoid mutable state, and reassign variables only in rare cases when it is really necessary. We don't want to manually enforce immutability, we suppose that everything is immutable by default and want to bring additional attention to the cases when something is not. If you use final to mark non-mutable variables it means that you need to write more code for regular cases and less code in exceptional cases. (BTW in modern languages declaring immutable variables doesn't require writing additional code, but unfortunately not in Java).
Brian Goetz, Java Language Architect, also likes the way IntelliJ IDEA highlights reassigned variables (see his tweet).
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
edited yesterday
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
answered Aug 5 '18 at 19:49
CrazyCoderCrazyCoder
278k50657664
278k50657664
1
It's basically whatfinalcan be used for (only not everybody uses it)
– ACV
Jan 29 at 15:32
add a comment |
1
It's basically whatfinalcan be used for (only not everybody uses it)
– ACV
Jan 29 at 15:32
1
1
It's basically what
final can be used for (only not everybody uses it)– ACV
Jan 29 at 15:32
It's basically what
final can be used for (only not everybody uses it)– ACV
Jan 29 at 15:32
add a comment |
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I'm not sure, but if you use jdk 10 these underlings may suggest you that you can use
varinstead ofint.– zlakad
Aug 5 '18 at 18:32
Thanks for the reply. I actually downgraded to jdk 8/1.8, because nobody could open my jar :)
– fandango
Aug 5 '18 at 18:34
1
Well, it is unnecessary reassignment in the sense that you could just use a stream to calculate it... But I don't see that you are doing anything unusual there.
– Andy Turner
Aug 5 '18 at 18:46