Faulty Null-Check Suspected in ToolProvider

[Philipp Kunz]

Hi again,

I figured out and err deserve a null-check test as well. See patch.

I'm wondering, if or how a similar check could be applied as well to
ToolProvider.run(PrintWriter, PrintWriter, String...)
which currently is implemented (hopefully) by each tool having to
repeat the null-checks.

I'm also wondering about the call to flush in run(PrintStream out,
PrintStream err, String... args). It looks like the intention was to
flush the wrapping PrintWriter.
That is not possible without also flushing the underlying PrintStream.
BufferedWriter.flushBuffer would be a more sensible method to call but
is not accessible.
The effect is actually, that the call to PrintWriter.flush will also
call flush of the underlying PrintStream. Should that be documented
more explicitly, for example:

diff -r 7c17199fa37d
src/java.base/share/classes/java/util/spi/ToolProvider.java
--- a/src/java.base/share/classes/java/util/spi/ToolProvider.java	
Fri Feb 15 08:21:08 2019 -0500
+++ b/src/java.base/share/classes/java/util/spi/ToolProvider.java	
Sat Feb 16 09:17:46 2019 +0100
@@ -107,6 +107,8 @@
      * @implNote This implementation wraps the {@code out} and {@code
err}
      * streams within {@link PrintWriter}s, and then calls
      * {@link #run(PrintWriter, PrintWriter, String[])}.
+     * Both {@code out} and {@code err} streams are flushed before the
method
+     * returns as a side-effect of flushing the wrapping {@link
PrintWriter}s.
      *
      * @param out a stream to which "expected" output should be
written
      *


Regards,
Philipp
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