javax.tools.FileObject.toUri() generates URI without schema under Solaris OS.
A URI generated by a FileObject produced by a StandardJavaFileManager should start with 'file:'.
(Potentially it can be java.io.File problem)

test:
----------------------
import javax.tools.*;
import java.util.*;
import java.io.*;
import java.net.URI;

class test5 {
    public static void main(String[] argv){
        JavaCompilerTool compiler = ToolProvider.getSystemJavaCompilerTool();
        StandardJavaFileManager mgr = compiler.getStandardFileManager( new DiagnosticCollector<JavaFileObject>() );
        System.out.println( new File( new File(".").toURI() ).getAbsolutePath() );
        mgr.setLocation(StandardJavaFileManager.StandardLocation.CLASS_OUTPUT, 
                            Collections.singleton(new File( new File(".").toURI())));
        try {                            
            FileObject fo = mgr.getFileForOutput(StandardJavaFileManager.StandardLocation.CLASS_OUTPUT,
                                    "", URI.create("file.to.delete"), null);
            System.out.println( fo.toUri() );                                    
        } catch( IOException x ){
            x.printStackTrace(System.out);
        }
    }
}
----------------------

output under Solaris:
----------------------
it162333@~/tests>java -cp . test5
/home/it162333/tests/.
/home/it162333/tests/./file.to.delete
----------------------

output under Windows:
----------------------
Z:\tests>z:/lnks/jdk6/bin/java.exe -cp . test5
Z:\tests\.
file:/Z:/tests/./file.to.delete
----------------------
tests failed
> api/javax_tools/FileObject/index.html#All[delete0001]
> api/javax_tools/FileObject/index.html#All[getCharContent0001]
> api/javax_tools/FileObject/index.html#All[getCharContent0002]
> api/javax_tools/FileObject/index.html#All[getInputStream0001]
> api/javax_tools/FileObject/index.html#All[getLastModified0001]
> api/javax_tools/FileObject/index.html#All[getOutputStream0001]
> api/javax_tools/FileObject/index.html#All[openReader0001]
> api/javax_tools/FileObject/index.html#All[openWriter0001]
> api/javax_tools/FileObject/index.html#All[toUri0001]
> api/javax_tools/JavaFileObject/index.html#All[getKind0001]
Failing Test: javac/api/JFOTest05

Also FileObject.toUri() generates URI with one extra '.', which is not required.
Please see the attached testcase
<testcase>
import javax.tools.*;
import static javax.tools.StandardLocation.*;
import static javax.tools.JavaFileObject.Kind.*;
  
public class T6419926  {
  public static void main(String... arg) throws Exception {
      JavaCompilerTool javac =
      ToolProvider.getSystemJavaCompilerTool();
      JavaFileManager jfm = javac.getStandardFileManager(null);
      JavaFileObject jfo =
      jfm.getJavaFileForInput(CLASS_PATH,"Foo",SOURCE);
      System.out.println(jfo.toUri().toURL()); // to check - generates URI without schema.
      if(!jfo.toUri().toString().equals(jfo.toUri().resolve(
                        jfo.toUri()).toString())) // Extra dot is  not required.
          throw new Exception("Check the generated URI");
  }
}
</testcase>
Failing Tests: javac/api/JFOTest05, javac/api/JFOTest06
failing testcases: javac/api/JavaFileObject/JFOTest05 , javac/api/JavaFileObject/JFOTest06