Please see the following code

Case 1:

<code>
import java.io.Writer;
import javax.tools.*;
import javax.tools.JavaFileObject.Kind;
 
public class CompileFromString {
    public static void main(String... args) throws Exception {
        JavaCompilerTool compiler = ToolProvider.defaultJavaCompiler();
        compiler.setOption("-Xlint");
        compiler.run((Writer)null, (JavaFileObject)null);
    }
}

</code>

Output when executed it throws Null pointer but with the following details.

<output>
bash-2.05$ java CompileFromString
An exception has occurred in the compiler (1.6.0-internal). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
        at com.sun.tools.javac.main.JavaCompiler.readSource(JavaCompiler.java:289)
        at com.sun.tools.javac.main.JavaCompiler.parse(JavaCompiler.java:341)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:476)
        at com.sun.tools.javac.main.Main.compile(Main.java:662)
        at com.sun.tools.javac.Tool.run(Tool.java:106)
        at CompileFromString.main(CompileFromString.java:125)
bash-2.05$
</output>

Case 2:

When setOption() is removed then compiler throws different output. Please check the following code.

<code>
import java.io.Writer;
import javax.tools.*;
import javax.tools.JavaFileObject.Kind;
 
 
public class CompileFromString {
    public static void main(String... args) throws Exception {
        JavaCompilerTool compiler = ToolProvider.defaultJavaCompiler();
        //compiler.setOption("-Xlint");
        compiler.run((Writer)null, (JavaFileObject)null);
    }
}
</code>

Output of the code when executed.

<Output>
bash-2.05$ java CompileFromString
Usage: javac <options> <source files>
where possible options include:
  -g Generate all debugging info
  -g:none Generate no debugging info
  -g:{lines,vars,source} Generate only some debugging info
  -nowarn Generate no warnings
  -verbose Output messages about what the compiler is doing
  -deprecation Output source locations where deprecated APIs are u
sed
  -classpath <path> Specify where to find user class files
  -cp <path> Specify where to find user class files
  -sourcepath <path> Specify where to find input source files
  -bootclasspath <path> Override location of bootstrap class files
  -extdirs <dirs> Override location of installed extensions
  -endorseddirs <dirs> Override location of endorsed standards path
  -d <directory> Specify where to place generated class files
  -encoding <encoding> Specify character encoding used by source files
  -source <release> Provide source compatibility with specified release
  -target <release> Generate class files for specific VM version
  -version Version information
  -help Print a synopsis of standard options
  -X Print a synopsis of nonstandard options
  -J<flag> Pass <flag> directly to the runtime system

</Output>


###@###.### 2005-06-24 18:42:26 GMT
###@###.### 2005-06-25 02:28:04 GMT