-XX:HitachiCallToString (Option to output the local variable information)

Format

-XX:HitachiCallToString=applicable-range

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Description

The character string of a String object obtained for the local variable object from the class corresponding to the applicable-range is output as a character string that represents the variable value.

Note that if no objects are stored in the local variable, or if the object is a JavaVM internal object, the local variable information is not output.

Default value

• -XX:HitachiCallToString=minimal

Prerequisite options

• -XX:+HitachiLocalsInThrowable

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Argument

applicable-range

Specify minimal or full.

minimal

The following classes in the java.lang package are applicable:

• String

• StringBuffer

• Boolean

• Byte

• Character

• Short

• Integer

• Long

• Float

• Double

Note that, even when null character ("") is specified, the applicable range will be same as "minimal".

full

All the classes and array types are applicable.

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Examples of output

The following is an example of output (simple output format) using the Java program example 3:

For -XX:HitachiCallToString=minimal

 at Example3.method(Example3.java:18)
  locals:
   (Example3) this = <0xaa07db58>
   (java.lang.String) l1 = <0xae173a28> "local 1"
   (java.lang.StringBuffer) l2 = <0xaa07dca0> "local 1 + local 2"
   (java.lang.Boolean) l3 = <0xaa07de18> "false"
   (java.lang.Character) l4 = <0xaa07df68> "X"
   (java.lang.Long) l5 = <0xaa07e078> "-9223372036854775808"
   (java.lang.Object) l6 = <0xaa07e1a8>
   (java.lang.Object[]) l7 = <0xaa07e298>
 at Example3.main(Example3.java:4)
  locals:
...

For -XX:HitachiCallToString=full

 at Example3.method(Example3.java:18)
  locals:
   (Example3) this = <0xaa07db58> "I am an Example3 instance."
   (java.lang.String) l1 = <0xae173a28> "local 1"
   (java.lang.StringBuffer) l2 = <0xaa07dca0> "local 1 + local 2"
   (java.lang.Boolean) l3 = <0xaa07de18> "false"
   (java.lang.Character) l4 = <0xaa07df68> "X"
   (java.lang.Long) l5 = <0xaa07e078> "-9223372036854775808"
   (java.lang.Object) l6 = <0xaa07e1a8> "Thread[Thread-0,5,main]"
   (java.lang.Object[]) l7 = <0xaa07e298> "[Ljava.lang.Thread;@26e431"
 at Example3.main(Example3.java:4)
  locals:
...

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Precautions

• To collect complete local variable information, while you are creating the class file in javac, you need to add the -g option or the -g:vars option and fill the local variable information in the class file. For the class file created without adding the -g option or the -g:vars option, the local variable information is output in the collectable range.

• When you specify this option and execute a Java program using AWT or Swing, specify minimal (default) in applicable-range. If you specify full in applicable-range, the program might not operate correctly.

• Specify full in applicable-range only when you investigate the cause of an exception that occurred in a user program. If full is specified, the toString() method for a local variable object is invoked when an exception object is generated. When the toString() method is invoked, information useful for cause investigation can be obtained. However, because the method is invoked at an irregular timing, the product or user program might not be able to operate correctly.

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