Removing blank line from end of result in java

This is what my result looks like:

1.*********
2.*********
3.*********
4.*********
5.*********
6.*********
7.

I need to remove the blank line 7

Here is my code:

public static String getRectangle(int maxRows, int maxCols, char symbol) {
    new UnsupportedOperationException("You must implement this method.");
    if (maxRows<1 || maxCols<1) { 
	    return null; 
	} else { 
		String result = "";
		for (int i = 0; i < maxRows; i++) { 
		    for (int j = 0; j < maxCols; j++) { 
				result = result + symbol;
            } 
			result = result + "\n";
        } 
		return result;	 
	}
}

Add a condition here:

if (i != maxRows - 1) {
    result = result + "\n";
}

Although i would suggest using a StringBuilder instead of a string to store the result.

You don't need any extra conditions. Just replace return result with return result.trim()

Since the Java version wasn't specified, as of Java 11, you can use String::repeat with amended number of rows and columns:

public static String getRectangle(int maxRows, int maxCols, char symbol) {
	if (maxRows<1 || maxCols<1) {
		return null;
	} else {
		String row = String.valueOf(symbol).repeat(maxCols);  // create a row
		String columns = (row + "\n").repeat(maxRows - 1);    // create n-1 columns 
		return columns + row;                                 // append the last column 
                                                              // .. without the new line
	}
}

If you are stick with a lower version of Java, use StringBuilder. The advantage of this class is they can be used with each other:

public static String getRectangle(int maxRows, int maxCols, char symbol) {
	if (maxRows<1 || maxCols<1) {
		return null;
	} else {
		StringBuilder row = new StringBuilder();
		StringBuilder column = new StringBuilder();
		for (int i = 0; i < maxCols; i++) {        // rows
			row.append(symbol);
		}
		for (int i = 0; i < maxRows - 1; i++) {    // n-1 columns
			column.append(row).append("\n");
		}
		return column.append(row).toString();      // append the last one w/o a new line
	}
}

Just adding a simple condition will help

    public static String getRectangle(int maxRows, int maxCols, char symbol) {
//        new UnsupportedOperationException("You must implement this method.");
        if (maxRows < 1 || maxCols < 1) {
            return null;
        } else {
            String result = "";
            for (int i = 0; i < maxRows; i++) {
                for (int j = 0; j < maxCols; j++) {
                    result = result + symbol;
                }
                if (i != maxRows - 1) result = result + "\n";
            }
            return result;
        }
    }

Another way to build a repeated rectangle without the trailing new line is to use combination of ancient Collections.nCopies and String.join (Java 8+):

public static String getRectangle(int maxRows, int maxCols, char symbol) {
    if (maxRows<1 || maxCols<1) {
        return null;
    }
    String row = String.join("", Collection.nCopies(maxCols, String.valueOf(symbol)));
    return String.join("\n", Collections.nCopies(maxRows, row));                                
}