Hi all,
I am using R and JRI under Windows XP Pro. I am posting this question
here since the reason might be R related (since I am running an R
script) but there is also a very good chance that it is JRI only
(since I am using the JRI interface to activate the script) -- in
which case I want to apologize for misplacing this message.
I have a method that instantiates an REngine object every time it is
called. It runs a script provided by a file name and closes REngine
afterward. The script works fine, the png file is successfully
generated and the PNG file is released so that I can delete it if I
want ( but I don't in that case). For some strange reason, when
running this code twice I get the following error: upon which the Java
Virtual machine dies on me.
Any explanation would be greatly appreciated!
Best,
Ralf
Here the Java code, the R code, and the Java VM error:
++++++++++++++++ START JAVA CODE ++++++++++++++++++
/** Helper method */
private static void eval(Rengine r, String s) {
r.eval(s, false);
}
/** Assigns the given java value to the given R variable name */
private static void assign(Rengine r, String rVariableName, String javaValue) {
r.assign(rVariableName, javaValue);
}
public void run() throws Exception {
String filepath = this.path;
if (filepath != null) {
File rFile = new File(filepath );
if (rFile.exists()) { // run R script
// start R engine
if (!Rengine.versionCheck()) {
System.err.println("** Version mismatch
- Java files don't match
library version.");
System.exit(1);
}
// creating R engine
Rengine rEngine = new Rengine(null, false, new
EmptyCallbacks());
// the engine creates R is a new thread, so we
should wait until it's ready
if (!rEngine.waitForR()) {
System.out.println("Cannot load R for "
+ this.getClass().getName());
return;
}
// executing logic
try {
assign(rEngine, "filename", filepath);
eval(rEngine, "source(filename)");
} catch (Exception e) {
System.out.println(this.getClass().getName() + ": Error in R code: " + e);
e.printStackTrace();
// stopping R engine
System.out.println("Error when running
script - rEngine stopped!");
if (rEngine != null){
rEngine.end();
}
}
// stopping R engine
rEngine.end();
} else {
throw new Exception(getClass().getName() + " not run -
missing
R file - location: " + rFile.getAbsolutePath());
}
}
}
+++++++++++++++++++++ END JAVA CODE +++++++++++++++++++++++++
+++++ START R Code ++++++++
library(RJDBC)
# db connection
driver <- JDBC("com.mysql.jdbc.Driver","lib/mysql-connector-java-5.0.6-bin.jar")
con <- dbConnect(driver, "jdbc:mysql://localhost/mydb", "xxx", "yyy")
# list tables
dbListTables(con)
# user, task and event information
result = dbGetQuery(con, "SELECT x,y from mytable;")
png(file="output.png")
plot(result$x, result$y)
dev.off()
+++++ START R Code ++++++++
ERROR:
#
# An unexpected error has been detected by Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=...., pid=5400, tid=3204
#
# Java VM: Java HotSpot(TM) Client VM (11.2-b01 mixed mode, ....)
# Problematic frame:
# C [R.dll+0x1136fe]
#
# An error report file with more information is saved as:
# ....
[WARN] 404 - GET /output.png (127.0.0.1) 1402 bytes
Request headers
Host: localhost:8888
User-Agent: ....
Accept: image/png,image/*;q=0.8,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Referer: http://localhost....
Response headers
Content-Length: 1402
Content-Type: text/html; charset=iso-8859-1
#
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#
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