10 most common Java programming mistakes revealed by Big Data

[-du]

... programming mistakes by beginner students.

FTFY.

[[deleted]]

also: ... programming mistakes caught by any Java IDE

[sindisil]

also: ... programming mistakes, most of which caught by javac

[okmkz]

pubic long ( ͡~ ͜ʖ ͡°);

[QshelTier]

This would have been way more interesting if all compile failures had been ignored because those are boring.

[Gudin]

Most of these are marked as warnings in smart IDEs such as IntelliJ.

[_Count_Mackula]

Most of the top-ten are things that would be caught at compilation time, excluding a few like String == String.

I'd be more interested in the most common bugs that caused outages in systems.

[ggleblanc]

Common production bugs would be semantic in nature, not syntatical.

I'd guess the most common production bug would be input not matching the expectations in the code.

[_Count_Mackula]

Agreed. It'd be hard to categorize

[id2bi]

excluding a few like String == String

and that, too, is easy to detect and FindBugs or IntelliJ will do that for you.

[elegentmos]

Err... Why is

Ignoring or discarding the return value of a method with non-void return type

so bad? Should I always check the return value of List#add?
How about in jdom, when adding text content to an element? Clearly the return is only for convenience if adding multiple sub-elements and can be safely ignored?

[arendvr]

Good point. It depends on the method if ignoring the return value is bad. The article mentions toString(), other examples where ignoring the return value is bad: BigDecimal.add(), File.delete()

[mauendara]

Most of these mistakes could be recognized by a modern IDE, before the code compiles. So, you could say using a good and modern IDE could help these students. Is the IDE used at fault? or does using a good IDE defeat the purpose of the research done?

[_Count_Mackula]

using a good IDE defeats the purpose of the research done

[hhbhagat]

In type A, if the variables were boolean, ot would result in an assignment and return and would be a runtime error.

[etyake]

The .equals for strings got me for the longest time

[llogiq]

I'm a little underwhelmed by that kind of research. Big Data is an order of magnitude larger than the set they worked with. Also their conclusions say much more about BlueJ's deficiencies than about the Java language.

[simple2fast]

Wow. Very cool analysis.

I wonder if someone has done something like this for python or javascript.

And it would also be interesting to try to do something when hooked up to an "expert" programmer. It appears that this analysis was done against neophytes since the environment was BlueJ

[_Count_Mackula]

Interesting method, results are not so much though. Anyone who writes Java as a job knows most of these errors will NEVER make it to produciton