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Code Analyzer for Java

There is a newer version: 8.10.0.38194

Why is this an issue?
When directly subclassing java.io.OutputStream or java.io.FilterOutputStream, the only requirement is that you implement
the method write(int). However most uses for such streams don’t write a single byte at a time and the default implementation for
write(byte[],int,int) will call write(int) for every single byte in the array which can create a lot of overhead and is
utterly inefficient. It is therefore strongly recommended that subclasses provide an efficient implementation of
write(byte[],int,int).
This rule raises an issue when a direct subclass of java.io.OutputStream or java.io.FilterOutputStream doesn’t provide an
override of write(byte[],int,int).
Noncompliant code example
public class MyStream extends OutputStream { // Noncompliant
    private FileOutputStream fout;

    public MyStream(File file) throws IOException {
        fout = new FileOutputStream(file);
    }

    @Override
    public void write(int b) throws IOException {
        fout.write(b);
    }

    @Override
    public void close() throws IOException {
        fout.write("\n\n".getBytes());
        fout.close();
        super.close();
    }
}

Compliant solution
public class MyStream extends OutputStream {
    private FileOutputStream fout;

    public MyStream(File file) throws IOException {
        fout = new FileOutputStream(file);
    }

    @Override
    public void write(int b) throws IOException {
        fout.write(b);
    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        fout.write(b, off, len);
    }

    @Override
    public void close() throws IOException {
        fout.write("\n\n".getBytes());
        fout.close();
        super.close();
    }
}

Exceptions
This rule doesn’t raise an issue when the class is declared abstract.