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Unable to write values into excel using multiple workbook.write methods

The below code is working without any runtime error if I call the owb.write(fileOut) and fileOut.close() method only once at at the ending (commented as write and close positioning) but the problem here is that the first value to be set when k=1, is not being printed in the workbook. It works fine when the iteration is in other columns and k=1.Only the first iteration is not being printed. Rest of the values are being set correctly.
I tried using multiple workbook.write() method. If you look at the below code, commented as [1], I had to invoke owb.write(fileOut) separately in the if condition(commented as if condition[1]) and else condition(commented as else condition [2]) because as I said, first value was not getting set in the workbook. I am getting the following runtime error while trying to execute the code in this scenario: Fail to save: an error occurs while saving the package : The part /docProps/app.xml fail to be saved in the stream with marshaller org.apache.poi.openxml4j.opc.internal.marshallers.DefaultMarshaller#3740f768
for(int i=0;i<noOfCols1;i++)
{
for(int j=1;j<=noOfRows1;j++)
{
value1 = formatter.formatCellValue(sheet1.getRow(j).getCell(i));
for(int m=1;m<=noOfRows2;m++)
{
value2 = formatter.formatCellValue(sheet2.getRow(m).getCell(i));
value1= value1.trim();
value2=value2.trim();
int value2Position = sheet2.getRow(m).getCell(i).getRowIndex();
if(!positions.contains(value2Position))
{
if(value1.contentEquals(value2))
{
positions.add(value2Position);
matched = true;
}
else{
matched = false;
}
}
if(matched==true)
{
break;
}
}
if(matched == false)
{
int k=1;
if(cFilledPositions.isEmpty()) //If condition[i]
{
rowHead = sheet.createRow((short)k);
rowHead.createCell(i).setCellValue(value1);
owb.write(fileOut); //[1]
}
else //else condition [1]
{
int l = cFilledPositions.size()-1;
k = cFilledPositions.get(l)+1;
rowHead = sheet.createRow((short)k);
rowHead.createCell(i).setCellValue(value1);
owb.write(fileOut);
}
cFilledPositions.add(k);
}
matched = false;
}
cFilledPositions.clear();
positions.clear();
}
//write and close positioning
fileOut.close();

I tried debugging and found that the createRow() method deletes the values previously created if called again on the same row.
To elaborate this, suppose the sheet.createRow() sets the value of a cell in the first iteration, and when it finishes its iteration in the j for loop, the cFilledPositions list is cleared and while it comes back after going to the main loop, 'cFilledPositionswill be empty and the integerkwill again be initialized to1. This is whencreateRow(k)` which is 1 is called again. This would flush out the previously existing values in the 1st row. I am trying to figure out a work around for this and will edit my answer with the solution if I my code works.
Below was the work around. I checked if the row is empty. The createRow function is called only when the row is empty. I have added the comments for the new code.
for(int i=0;i<noOfCols1;i++)
{
for(int j=1;j<=noOfRows1;j++)
{
value1 = formatter.formatCellValue(sheet1.getRow(j).getCell(i));
for(int m=1;m<=noOfRows2;m++)
{
value2 = formatter.formatCellValue(sheet2.getRow(m).getCell(i));
value1= value1.trim();
value2=value2.trim();
int value2Position = sheet2.getRow(m).getCell(i).getRowIndex();
if(!positions.contains(value2Position))
{
if(value1.contentEquals(value2))
{
positions.add(value2Position);
matched = true;
}
else{
matched = false;
}
}
if(matched==true)
{
break;
}
}
if(matched == false)
{
int k=1;
if(cFilledPositions.isEmpty())
{
try{
isEmpty = checkIfRowIsEmpty(sheet,k,formatter);
if(isEmpty)
{
rowHead = sheet.createRow(k);
}
rowHead.createCell(i).setCellValue(value1);
}
catch (Exception e){
try{
rowHead = sheet.createRow(k);
rowHead.createCell(i).setCellValue(value1);
}
catch (Exception e1){
}
}
}
else
{
int l = cFilledPositions.size()-1;
k = cFilledPositions.get(l)+1;
try{
isEmpty = checkIfRowIsEmpty(sheet,k,formatter);
if(isEmpty)
{
rowHead = sheet.createRow(k);
}
rowHead.createCell(i).setCellValue(value1);
}
catch (Exception e)
{
try{
rowHead = sheet.createRow(k);
rowHead.createCell(i).setCellValue(value1);
}
catch (Exception e1){
}
}
}
cFilledPositions.add(k);
}
matched = false;
}
cFilledPositions.clear();
positions.clear();
}

Variable not adding 1 to itself inside if statement

I have this method.
int m = 0;
int a = 0;
#Override
public void animate(long deltaMs){
...
a++;
double valor = destValue * 100f;
if(a%17==0 && valor > 1) {
MySQLAccess sql = new MySQLAccess();
int p = 0;
try {
p = sql.getRandom();
} catch (Exception e) {
}
m++;
if(m == p+1) {
MainFrame mf = new MainFrame();
RandomProvider randomp = new RandomProvider();
QueryPanel qp = new QueryPanel(randomp);
try {
sql.insertScore(valor,sql.getUsuarios(qp.getUsuario()),
sql.getRandom());
} catch (Exception e) {
e.printStackTrace();
}
}
}
repaint();
}
}
This method executes itself multiple times on runtime, and I wanted to keep track of how many times it did, the variable "a" does get added correctly but "m" that is inside the if statement doesn't and I don't know why, I need to know how many times that if statement runs.

Since you want to know how many times the if statement run (and you don’t use debugger), store those times in a variable.
//...
int timesRun = 0;
while( ){
if( ){
timesRun++;
}
}
System.out.println(“Debug: I’d statement run”+timesRun+” times”);

if MySQLAccess sql = new MySQLAccess() throws, m++ will not be reached.

While else statement equivalent for Java?

What is the Java equivalent of the while/else in Python? Because it doesn't work in Java. The first chunk was my python code and the second portion is my attempt to translate it into Java. Edit: tring to replicate while-else
while temp.frontIsClear():
if temp.nextToABeeper():
temp.pickBeeper()
count += 1
temp.move()
else:
if temp.nextToABeeper():
temp.pickBeeper()
count += 1
print "The count is ", count
Java Attempt
Robot temp = new Robot();
int count = 0;
while (temp.frontIsClear())
{
if (temp.nextToABeeper())
{
temp.pickBeeper();
count += 1;
}
temp.move();
}
else
{
if (temp.nextToABeeper())
{
temp.pickBeeper();
count += 1;
}
}
print ("The count is ", count);

The closest Java equivalent is to explicitly keep track of whether you exited the loop with a break... but you don't actually have a break in your code, so using a while-else was pointless in the first place.
For Java folks (and Python folks) who don't know what Python's while-else does, an else clause on a while loop executes if the loop ends without a break. Another way to think about it is that it executes if the while condition is false, just like with an if statement.
A while-else that actually had a break:
while whatever():
if whatever_else():
break
do_stuff()
else:
finish_up()
could be translated to
boolean noBreak = true;
while (whatever()) {
if (whateverElse()) {
noBreak = false;
break;
}
doStuff();
}
if (noBreak) {
finishUp();
}

Just use one more if statement:
if (temp.nextToABeeper())
// pick beer
} else {
while (temp.frontIsClear()) { /* your code */ }
}
Or:
if (temp.frontIsClear())
while (temp.frontIsClear()) { /* your code */ }
} else if (temp.nextToABeeper()) {
// pick beer
}

If you look at the Java Backus–Naur form Grammar (Syntax Specification), else never follows a while.
Your solution needs to be modified accordingly. You can put the while in an else, that way you handle the if statement.
if temp.nextToBeeper() {
//handle
} else {
while(temp.frontIsClear()) {
//handle
}
}

Try this:
Robot temp = new Robot();
int count = 0;
if (temp.frontIsClear())
{
while (temp.frontIsClear())
{
if (temp.nextToABeeper())
{
temp.pickBeeper();
count += 1;
}
temp.move();
}
}
else if (temp.nextToABeeper())
{
temp.pickBeeper();
count += 1;
}
print ("The count is ", count);

In Java
if is a conditional statement .
But
while is loop that is iterate again an again and stop itself when falsecondition occurred .

Is performance gained when using continue in a for-loop with many if-statements?

I have a for loop in a java program which iterates through a set of maps.
Inside the loop I have around 10 different if-statements which checks the name of each key inside the each map.
Example:
for (<String, Object> map : object.entrySet()) {
if (map.getKey().equals.("something") {
do_something;
continue;
}
if (map.getKey().equals.("something_else") {
do_something_else;
continue;
}
if ...
}
Do I gain any performance when adding continue-statements like this?
When I step through my code in my IDE and NOT have these continue statements, each if-statement will be tested even if the first one matches.
If I have them like this and the first if matches, the for loop will skip the next 9 if-statements and continue with the next object.
Maybe the compiled code will treat it differently and the added continue-statements actually makes the loop slower?

Instead of using continue all the time, do the getKey() just once and use else if:
for (Map.Entry<String, Object> entry : map.entrySet()) {
String key = entry.getKey();
if (key.equals("something")) {
// ...
} else if (key.equals("something else")) {
// ...
}
}
Or use a switch statement:
for (Map.Entry<String, Object> entry : map.entrySet()) {
switch (entry.getKey()) {
case "something":
// ...
break;
case "something else":
// ...
break;
}

If you want the current iteration to end after the first condition evaluates to true, you should use if-else-if-...-else. In my opinion, that's more clear than using continue, since that's what this syntax exists for.
for (<String, Object> map : object.entrySet()) {
if (map.getKey().equals.("something") {
do_something;
}
else if (map.getKey().equals.("something_else") {
do_something_else;
}
else if (...) {
...
}
... else {
...
}
}

With your current implementation, yes you are gaining a performance boost by skipping the remaining if statements using the continue keyword, although with only a constant of ten "if" statements, it's not that bad (10n = O(n) time). Having said that, the more practical way to approach this, as Eran stated, is to make use of else if statements, which will achieve the same result that you are currently using.

Because you have just a few values, IMO, you'll have a real performance improvement here if you map your strings to ints, since the int comparison is far faster than a String comparison.
Check this out
public class Lab1 {
public static void main(String[] args) {
usingStrings();
usingInts();
}
private static void usingInts() {
int[] samples = new int[100000000];
int[] values = {1,2,3,4};
for(int i=0;i<samples.length-1;i++) {
samples[i] = values[(int)(Math.random()*values.length)];
}
int total = 0;
long ini = System.currentTimeMillis();
for(int i=0;i<samples.length-1;i++) {
if (1 == (samples[i])) {
total+=doSomeJob();
}else if (2 == (samples[i])) {
total+=doSomeJob();
}else if (3 == (samples[i])) {
total+=doSomeJob();
}else {
total+=doSomeJob();
}
}
long end = System.currentTimeMillis();
System.out.println("Ints="+(end-ini));
}
private static void usingStrings() {
String[] samples = new String[100000000];
String[] values = {"one mule","two mules","three mules","four mules"};
for(int i=0;i<samples.length-1;i++) {
samples[i] = values[(int)(Math.random()*values.length)];
}
int total = 0;
long ini = System.currentTimeMillis();
for(int i=0;i<samples.length-1;i++) {
if ("one mule".equals(samples[i])) {
total+=doSomeJob();
}else if ("two mules".equals(samples[i])) {
total+=doSomeJob();
}else if ("three mules".equals(samples[i])) {
total+=doSomeJob();
}else {
total+=doSomeJob();
}
}
long end = System.currentTimeMillis();
System.out.println("Strings="+(end-ini));
}
/**
*
*/
private static int doSomeJob() {
int c = 0;
for(int i=0;i<1000;i++) {
c++;
}
return c;
}
}
output
Strings=962
Ints=6
which is actually how DBMS indexes work behind the scenes

Java - add a return statement

I am learning java so bear with me on this if it seems basic. I have a method which I am trying to edit to return a value which is 'read in' - I am trying to return 'move'. However, due to the setup of the code the return falls outside the code block and forces me to return a null. Can someone edit the code so that it returns the 'move' value? I have been working on this for 2 days and I can't work it out - the try and catch seem to be causing the problem
public Move listenToEngineMove()
{
synchronized(engineReadBuffer)
{
int numRows=engineReadBuffer.size();
if(numRows==0);
for(int kk=0; kk<numRows; kk++)
{
String row=engineReadBuffer.get(kk);
row=row.toLowerCase();
if((row.contains("move "))||(row.contains(" ... ")))
if((!row.contains("illegal"))&&(!row.contains("error")))
try {
String[] tokens=row.replaceAll("\\<.*\\>"," ").split("\\s+");
Move move = new Move(tokens[tokens.length-1]);
jcb.makeAIsMove(move);
System.out.println("thread.... " + row);
}
catch (Exception x) {
System.out.println("Exception! : "+x.getMessage());
}
}
engineReadBuffer.clear();
}
return null;
}

Try this:
public Move listenToEngineMove() {
Move move = null;
synchronized (engineReadBuffer) {
int numRows = engineReadBuffer.size();
if (numRows == 0) ; // what on earth is this?
for (int kk = 0; kk < numRows; kk++) {
String row = engineReadBuffer.get(kk);
row = row.toLowerCase();
if ((row.contains("move ")) || (row.contains(" ... ")))
if ((!row.contains("illegal")) && (!row.contains("error")))
try {
String[] tokens = row.replaceAll("\\<.*\\>", " ").split("\\s+");
move = new Move(tokens[tokens.length - 1]);
jcb.makeAIsMove(move);
System.out.println("thread.... " + row);
} catch (Exception x) {
System.out.println("Exception! : " + x.getMessage());
}
}
engineReadBuffer.clear();
}
return move;
}
I'd recommend that you replace this:
catch(Exception x){System.out.println("Exception! : "+x.getMessage());}
with this:
catch(Exception e){
e.printStackTrace(); // Or, better yet, logging with Log4J
}
The complete stack trace gives more info than the message.
This line looks like a mistake to me. The semi-colon at the end looks out of place.
if (numRows == 0) ; // what on earth is this?
Your code looks awful. I find it hard to read, because you aren't consistent with your indentation and general code style. Style matters; it makes your code easier to read and understand. Adopt a better style and stick with it.

You will need to move 'Move' just inside synchronized block, It is important to keep it inside synchronized block to stay thread safe.
public Move listenToEngineMove()
{
synchronized(engineReadBuffer)
{
Move move =null;
int numRows=engineReadBuffer.size();
if(numRows==0);
for(int kk=0; kk<numRows; kk++)
{
String row=engineReadBuffer.get(kk);
row=row.toLowerCase();
if((row.contains("move "))||(row.contains(" ... ")))
if((!row.contains("illegal"))&&(!row.contains("error")))
try {
String[] tokens=row.replaceAll("\\<.*\\>"," ").split("\\s+");
move = new Move(tokens[tokens.length-1]);
System.out.println("thread.... " + row);
}
catch(Exception x){System.out.println("Exception! : "+x.getMessage());}
}
engineReadBuffer.clear();
return move;//this is inside synchronized block
}
}