# Remove Redundant Close
# Description
In Java, the try-with-resource statements are able to automatically close the resources which are defined in the try-with-resource header.
Thus, any explicit close() (opens new window) invocation in the try block is redundant and potentially confusing.
This rule eliminates redundant resource close() invocations.
# Benefits
Applying this rule removes unnecessary code.
# Tags
# Code Changes
# Remove Close For One Resource
Pre
try (BufferedReader br = new BufferedReader(new FileReader(path))) {
System.out.println("First line: " + br.readLine());
br.close();
} catch (IOException e) {
e.printStackTrace();
}
Post
try (BufferedReader br = new BufferedReader(new FileReader(path))) {
System.out.println("First line: " + br.readLine());
} catch (IOException e) {
e.printStackTrace();
}
# Remove Close For Resource Declared Outside The Header
Pre
BufferedReader br = new BufferedReader(new FileReader(path));
try (br) {
System.out.println("First line: " + br.readLine());
br.close();
} catch (IOException e) {
e.printStackTrace();
}
Post
BufferedReader br = new BufferedReader(new FileReader(path));
try (br) {
System.out.println("First line: " + br.readLine());
} catch (IOException e) {
e.printStackTrace();
}
# Remove Close For Multiple Resources
Pre
try (BufferedReader br = new BufferedReader(new FileReader(path));
BufferedReader br2 = new BufferedReader(new FileReader(path2))) {
System.out.println("First line of first file: " + br.readLine());
br.close();
System.out.println("First line of second file " + br2.readLine());
br2.close();
} catch (IOException e) {
e.printStackTrace();
}
Post
try (BufferedReader br = new BufferedReader(new FileReader(path));
BufferedReader br2 = new BufferedReader(new FileReader(path2))) {
System.out.println("First line of first file: " + br.readLine());
System.out.println("First line of second file " + br2.readLine());
} catch (IOException e) {
e.printStackTrace();
}
# Limitations
The 'close()'-invocation statement can only be removed if the resource is a local variable which is declared in the same scope.
Use a Java Refactoring Tool
No license required
You can review this refactoring on your code without a license by installing jSparrow to your Eclipse IDE. Install the plug-in from Eclipse IDE: Eclipse Marketplace.
System-wide Refactoring
Do you want to automate this refactoring (and many more) to your system-wide code? The automatic application of this system-wide refactoring can be unlocked by acquiring your jSparrow license.
