[R] calling java from R and using java time series double precision array

[Hurr]

No response, and I still cannot do it or find out where to learn.
JAVA CLASS SOURCE FOR R: 
public class Transf2R { 
  Transf2R transf2R; 
  public static void main(String[]args) { 
    Transf2R transf2R=new Transf2R(); transf2R.transf2R=transf2R;
transf2R.transf2R.main2(); 
  } 
  public final static void main2() { 
    //no code yet 
  } 
  public final static double con0dbl=10001; 
  public final static double[]con1Vec=new double[] {
10001,10002,10003,10004,10005,10006 }; 
  public final static double[][]con2Arr=new double[][] { {
10001,10002,10003,10004 },{ 20001,20002,20003,20004 },{
30001,30002,30003,30004 } }; 
  public final static double[][]arReturnMethod() { 
    double[][]retArr=new double[3][4]; for(int i=0;i<3;i++)for(int
j=0;j<4;j++)retArr[i][j]=i*1000+j; return(retArr); 
  } 
  public final static double[][]dbl2DimArRet4R(double[][]dbl2DimAr4R) {
return(dbl2DimAr4R); } 
  public final static double[]dbl1DimVcRet4R(double[]dbl1DimVc4R) {
return(dbl1DimVc4R); } 
  public final static double dblRet4R(double dbl4R) { return(dbl4R); } 
public final static double dblNum4R=Math.PI; 
}

R RUN OUTPUT: 
> library(rJava)
> .jinit()
> .jaddClassPath("C:/ad/j")
> print(.jclassPath())
[1] "C:\\Users\\ENVY17\\Documents\\R\\win-library\\2.13\\rJava\\java"
[2] "C:\\ad\\j"                                                      
> trnsfer2R <- .jnew("Transf2R")
> arj3x4Ret <- .jcall(trnsfer2R,returnSig="[[D","arReturnMethod")
> print(arj3x4Ret) 
[[1]]
[1] "Java-Array-Object[D:[D at 8813f2"

[[2]]
[1] "Java-Array-Object[D:[D at 1d58aae"

[[3]]
[1] "Java-Array-Object[D:[D at 83cc67"

> arj3x4Ret <-
> sapply(.jcall(trnsfer2R,returnSig="[[D","arReturnMethod"),.jevalArray)
> print(arj3x4Ret) # note: row and column indices get interchanged 
     [,1] [,2] [,3]
[1,]    0 1000 2000
[2,]    1 1001 2001
[3,]    2 1002 2002
[4,]    3 1003 2003
> dblNum <- .jcall(trnsfer2R,returnSig="D","dblRet4R",trnsfer2R$dblNum4R)
> print(dblNum,digits=20)
[1] 3.141592653589793116
> conn1Vec <-
> .jcall(trnsfer2R,returnSig="[D","dbl1DimVcRet4R",trnsfer2R$con1Vec) #
> con1Vec is java one dim array of double precision constants 
> print(conn1Vec) 
[1] 10001 10002 10003 10004 10005 10006
> conn2Arr <-
> .jcall(trnsfer2R,returnSig="[[D","dbl2DimArRet4R",trnsfer2R$con2Arr) #
> con2Arr is java two dim array of double precision constants 
Error in .jcall(trnsfer2R, returnSig = "[[D", "dbl2DimArRet4R",
trnsfer2R$con2Arr) : 
  method dbl2DimArRet4R with signature ()[[D not found
> conn2Arr <-
> sapply(.jcall(trnsfer2R,returnSig="[[D","dbl2DimArRet4R",trnsfer2R$con2Arr),.jevalArray)
> # con2Arr is java two dim array 
Error in .jcall(trnsfer2R, returnSig = "[[D", "dbl2DimArRet4R",
trnsfer2R$con2Arr) : 
  method dbl2DimArRet4R with signature ()[[D not found
> 

OBSERVATIONS AND QUESTIONS: 
1) sapply( ,.jevalArray) made arj3x4Ret correct 
2) sapply( ,.jevalArray) did not make conn2Arr correct 
3) dblNum and conn1Vec did not need sapply() 
4) returnSig="[[D" worked to get arj3x4Ret but not for conn2Arr 
5) row and column indices get interchanged in arj3x4Ret 
6) How do I transfer to dblNum, conn1Vec, and conn2Arr without the methods
in java? 
7) For large two dimensional arrays, are there two simultaneous copies
clogging up small computer memory? 


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