JDK 9 RFR of JDK-8155516: Suppress warnings from uses of deprecated Class.newInstance langtools

[Jonathan Gibbons]

Joe,

I guess this is OK for now, but as a general policy for langtools, I 
hope we are not going to see @SuppressWarnings proliferating throughout 
the code.  If a method has been deprecated, it is presumably for a good 
reason (<cough> Optional.get </cough>) and there should in general be a 
replacement, and we should endeavor to improve the quality of the code 
base by using the recommended replacements, rather than perpetuating the 
sins of our predecessors.

As for @SuppressWarnings, the review yesterday had a credible use of the 
annotation insofar as the replacement method was not available in JDK 8, 
which (for the duration of JDK 9 development) is our bootstrap compiler.

For all of Stuart's protestations that these are not breaking changes, 
we are sure doing a lot of high priority reacting to non-breaking changes!

-- Jon

On 04/27/2016 04:21 PM, Jonathan Gibbons wrote:
> What is the recommended approach for avoiding the issue, as compared 
> to sweeping it under the carpet?
>
> -- Jon
>
>
> On 04/27/2016 02:27 PM, Joseph D. Darcy wrote:
>> Hello,
>>
>> As part of the effort to address
>>
>>     JDK-6850612: Deprecate Class.newInstance since it violates the 
>> checked exception language contract
>>
>> the uses of Class.newInstance in the langtools repo have to be 
>> address in some way, either by suppressing the resulting warning or 
>> by refactoring the code to use other recommended idioms.
>>
>> Please review the fix for
>>
>>     JDK-8155516: Suppress warnings from uses of deprecated 
>> Class.newInstance langtools
>>     http://cr.openjdk.java.net/~darcy/8155516.0/
>>
>> which takes the suppression approach.
>>
>> Patch below.
>>
>> Thanks,
>>
>> -Joe
>>
>> --- old/src/java.compiler/share/classes/javax/tools/ToolProvider.java 
>> 2016-04-27 14:16:21.269126143 -0700
>> +++ new/src/java.compiler/share/classes/javax/tools/ToolProvider.java 
>> 2016-04-27 14:16:21.177126140 -0700
>> @@ -123,7 +123,9 @@
>>      private static <T> T getSystemTool(Class<T> clazz, String 
>> moduleName, String className) {
>>          if (useLegacy) {
>>              try {
>> -                return Class.forName(className, true, 
>> ClassLoader.getSystemClassLoader()).asSubclass(clazz).newInstance();
>> +                @SuppressWarnings("deprecation")
>> +                T result = Class.forName(className, true, 
>> ClassLoader.getSystemClassLoader()).asSubclass(clazz).newInstance();
>> +                return result;
>>              } catch (ReflectiveOperationException e) {
>>                  throw new Error(e);
>>              }
>> --- 
>> old/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java 
>> 2016-04-27 14:16:21.573126153 -0700
>> +++ 
>> new/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java 
>> 2016-04-27 14:16:21.489126150 -0700
>> @@ -282,6 +282,7 @@
>>
>>          if (options.isSet(XPRINT)) {
>>              try {
>> +                @SuppressWarnings("deprecation")
>>                  Processor processor = 
>> PrintingProcessor.class.newInstance();
>>                  processorIterator = List.of(processor).iterator();
>>              } catch (Throwable t) {
>> @@ -549,8 +550,9 @@
>>                          try {
>>                              Class<?> processorClass = 
>> processorCL.loadClass(processorName);
>>                              ensureReadable(processorClass);
>> -                            processor =
>> -                                (Processor) 
>> (processorClass.newInstance());
>> +                            @SuppressWarnings("deprecation")
>> +                            Object tmp = processorClass.newInstance();
>> +                            processor = (Processor) tmp;
>>                          } catch (ClassNotFoundException cnfe) {
>> log.error("proc.processor.not.found", processorName);
>>                              return false;
>> --- 
>> old/src/jdk.compiler/share/classes/com/sun/tools/sjavac/options/Option.java 
>> 2016-04-27 14:16:21.881126163 -0700
>> +++ 
>> new/src/jdk.compiler/share/classes/com/sun/tools/sjavac/options/Option.java 
>> 2016-04-27 14:16:21.797126161 -0700
>> @@ -151,6 +151,7 @@
>>              // Construct transformer
>>              try {
>>                  Class<?> trCls = Class.forName(classname);
>> +                @SuppressWarnings("deprecation")
>>                  Transformer transformer = (Transformer) 
>> trCls.newInstance();
>>                  transformer.setExtra(extra);
>>                  helper.addTransformer(suffix, transformer);
>> --- 
>> old/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/taglets/TagletManager.java 
>> 2016-04-27 14:16:22.181126173 -0700
>> +++ 
>> new/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/taglets/TagletManager.java 
>> 2016-04-27 14:16:22.097126171 -0700
>> @@ -247,6 +247,7 @@
>>              tagClassLoader = fileManager.getClassLoader(TAGLET_PATH);
>>              Class<?> customTagClass = 
>> tagClassLoader.loadClass(classname);
>>              ensureReadable(customTagClass);
>> +            @SuppressWarnings("deprecation")
>>              Object instance = customTagClass.newInstance();
>>              Taglet newLegacy = new 
>> UserTaglet((jdk.javadoc.doclet.taglet.Taglet)instance);
>>              String tname = newLegacy.getName();
>> --- 
>> old/src/jdk.javadoc/share/classes/jdk/javadoc/internal/tool/Start.java 2016-04-27 
>> 14:16:22.481126183 -0700
>> +++ 
>> new/src/jdk.javadoc/share/classes/jdk/javadoc/internal/tool/Start.java 2016-04-27 
>> 14:16:22.393126180 -0700
>> @@ -252,7 +252,9 @@
>>              initMessager();
>>              messager.setLocale(locale);
>>              try {
>> -                doclet = (Doclet) docletClass.newInstance();
>> +                @SuppressWarnings("deprecation")
>> +                Object o = docletClass.newInstance();
>> +                doclet = (Doclet) o;
>>              } catch (InstantiationException | IllegalAccessException 
>> exc) {
>>                  exc.printStackTrace();
>>                  if (!apiMode) {
>>
>