I have found a source of Java compiler written in Ocaml which should work.
But when I do make, it finished with an error:
unzip.o: In function `camlUnzip__59':
(.data+0x540): undefined reference to `camlzip_deflateEnd'
unzip.o: In function `camlUnzip__59':
(.data+0x544): undefined reference to `camlzip_deflate'
unzip.o: In function `camlUnzip__59':
(.data+0x548): undefined reference to `camlzip_deflateInit'
collect2: ld returned 1 exit status
File "caml_startup", line 1, characters 0-1:
Error: Error during linking
make: *** [javacx] Error 2
It is odd that the file "caml_startup" even does not exist in the folder. Could anyone help? Thank you very much.
caml_startup is part of the OCaml runtime.
The project's website mentions that it works with OCaml 3.09, which is quite old. It worked for me with 3.10 (which is still quite old; latest release is 3.12) - maybe it just doesn't work with more recent versions.
However, as a first guess, I would try simply deleting these definitions from unzip.ml - they are never called, and declare external routines which are not actually implemented (whereas other external routines in unzip.ml are implemented in zlib.c):
external deflate_init: int -> bool -> stream = "camlzip_deflateInit"
external deflate:
stream -> string -> int -> int -> string -> int -> int -> flush_command
-> bool * int * int
= "camlzip_deflate_bytecode" "camlzip_deflate"
external deflate_end: stream -> unit = "camlzip_deflateEnd"
Related
I am using the below code to walk a directory and fetch the first file . I am not able to fix the two sonar lint issues . Please help.
List<String> result = walk.filter(Files::isRegularFile).map(x -> x.toString()).collect(Collectors.toList());
Please make this change:
List<String> result = walk.filter(p -> p.toFile().isFile()).map(Path::toString).collect(Collectors.toList());
SonarLint also state the reason for the suggestion.
Lambdas should be replaced with method references
Java 8's "Files.exists" should not be used
Look at the 3725 Sonar rule :
The Files.exists method has noticeably poor performance in JDK 8, and
can slow an application significantly when used to check files that
don't actually exist.
The same goes for Files.notExists, Files.isDirectory and
Files.isRegularFile.
Note that this rule is automatically disabled when the project's
sonar.java.source is not 8.
Your project very probably relies on JDK/JRE 8.
If you dig into the OpenJDK issues you could see that on Linux the issue was partially solved but not on Windows.
About the second issue :
map(x -> x.toString())
Just replace it by a method reference :
map(Path::toString)
So finally to be compliant with Sonar, it gives :
//FIXME use Files::isRegularFile when update with Java>8
List<String> result = walk.filter(p -> p.toFile().exists())
.map(Path::toString)
.collect(Collectors.toList());
What am I doing?
I am writing a data analysis program in Java which relies on R´s arulesViz library to mine association rules.
What do I want?
My purpose is to store the rules in a String variable in Java so that I can process them later.
How does it work?
The code works using a combination of String.format and eval Java and RJava instructions respectively, being its behavior summarized as:
Given properly formatted Java data structures, creates a data frame in R.
Formats the recently created data frame into a transaction list using the arules library.
Runs the apriori algorithm with the transaction list and some necessary values passed as parameter.
Reorders the generated association rules.
Given that the association rules cannot be printed, they are written to the standard output with R´s write method, capture the output and store it in a variable. We have converted the association rules into a string variable.
We return the string.
The code is the following:
// Step 1
Rutils.rengine.eval("dataFrame <- data.frame(as.factor(c(\"Red\", \"Blue\", \"Yellow\", \"Blue\", \"Yellow\")), as.factor(c(\"Big\", \"Small\", \"Small\", \"Big\", \"Tiny\")), as.factor(c(\"Heavy\", \"Light\", \"Light\", \"Heavy\", \"Heavy\")))");
//Step 2
Rutils.rengine.eval("transList <- as(dataFrame, 'transactions')");
//Step 3
Rutils.rengine.eval(String.format("info <- apriori(transList, parameter = list(supp = %f, conf = %f, maxlen = 2))", supportThreshold, confidenceThreshold));
// Step 4
Rutils.rengine.eval("orderedRules <- sort(info, by = c('count', 'lift'), order = FALSE)");
// Step 5
REXP res = Rutils.rengine.eval("rulesAsString <- paste(capture.output(write(orderedRules, file = stdout(), sep = ',', quote = TRUE, row.names = FALSE, col.names = FALSE)), collapse='\n')");
// Step 6
return res.asString().replaceAll("'", "");
What´s wrong?
Running the code in Linux Will work perfectly, but when I try to run it in Windows, I get the following error referring to the return line:
Exception in thread "main" java.lang.NullPointerException
This is a common error I have whenever the R code generates a null result and passes it to Java. There´s no way to syntax check the R code inside Java, so whenever it´s wrong, this error message appears.
However, when I run the R code in brackets in the R command line in Windows, it works flawlessly, so both the syntax and the data flow are OK.
Technical information
In Linux, I am using R with OpenJDK 10.
In Windows, I am currently using Oracle´s latest JDK release, but trying to run the program with OpenJDK 12 for Windows does not solve anything.
Everything is 64 bits.
The IDE used in both operating systems is IntelliJ IDEA 2019.
Screenshots
Linux run configuration:
Windows run configuration:
I am preparing an R wrapper for a java code that I didn't write myself (and in fact I don't know java). I am trying to use rJava for the first time and I am struggling to get the .jcall right.
Here is an extract of the java code for which I write a wrapper:
public class Model4R{
[...cut...]
public String[][] runModel(String dir, String initFileName, String[] variableNames, int numSims) throws Exception {
[...cut...]
dir and initFileName are character strings for the directory and file name with initial conditions, variable names is a list of character strings that I would write like this in R: c("var1", "var2", "var3", ...) and can be of length from one to five. Finally, numSim is an integer.
Here is my tentative R code for a wrapper function:
runmodel <- function(dir, inFile, varNames, numSim){
hjw <- .jnew("Model4R")
out <- .jcall(hjw, "[[Ljava/lang/String", "runModel", as.character(dir), as.character(inFile), as.vector(varNames), as.integer(numSim))
return(out)
}
The error in R is:
Error in .jcall(hjw, "[[Ljava/lang/String", "runModel", as.character(dir),
: method runModel with signature (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;II)[[Ljava/lang/String not found
I suspect that the JNI type isn't correct for String[][]. Anyhow, any help that could direct me towards a solution would be welcome!
You're missing a semicolon at the end of the JNI for String[][] - it should be "[[Ljava/lang/String;". Also, I think you need to call .jarray instead of as.vector on varNames. The R error is telling you that rJava thinks the class of the third argument is Ljava/lang/String; instead of [Ljava/lang/String;.
While compiling the code I get an unexpected error, which never occurred before, it says that I cannot convert from int to an Object...
Code:
maxBundles = max;
bundleProgressBar.setMaximum(max);
bundleProgressLabel.setText("Updating Components...");
// Tell JS that the state is Installing.
Object[] arr = { 1 };
error:
`103: error: incompatible types
[javac] Object[] arr = { 1 };`
I know this is a problem with eclipse, because it worked before, so my question is what can I change to resolve it...
What you're trying to do is called autoboxing - the process of converting a primitive (int in this case) to its Object represantation (Integer in this case), automatically. More on autoboxing and unboxing here.
Autoboxing was introduced in Java 1.5. So check that your project's compiler compliance level is set to 1.5 or above (Project properties -> Java compiler).
I just started to learn J2ME and right from the bat I got this error when using Random class. Arg, it's so frustrating. Anyone got the same problem before? I already tried to restart Eclipse, write only the code for the random generator to isolate it but to no avail.
I'm using CLDC 1.1 and MIDP 2.1 by the way.
Seems you are pointing out the wrong CLDC and MIDP libraries. new Random().nextInt(x) exists in CLDC 1.1.
If you are using CLDC 1.0 you can create your own implementation of nextInt(int):
public static int random(Random r, int n) {
if ((n & -n) == n) // i.e., n is a power of 2
return (int)((n * (long)r.nextInt()) >> 31);
int bits, val;
do {
bits = r.nextInt();
val = bits % n;
} while(bits - val + (n-1) < 0);
return val;
}
(Same implementation as nextInt(int) in the CLDC 1.1.)
nextInt(int) is only available since CLDC 1.1, so you have to specify CLDC 1.1 instead of 1.0
if you specified cldc 1.1 an still get this error its most likely an error of eclipse. took me hours to find:
in Eclipse go to Windows -> Preferences -> Java ME -> Device Management -> choose your Default Device -> Edit -> Libraries -> There you have to remove the cldc_1.0.jar
I had the same problem in netbeans, and solved it.
Right click on your project, go to properties.
Go To Libraries & Resources under build
Add Library
scroll for JMUnit for CLDC11
click OK
and build. all problems solved.
I just left JMUnit for CLDC11 there. not really sure if I need it. maybe I'll test without it once I have made up for lost time.