How to Print Line Numbers to the Log in Java

Android Log.d Print Line Number

Use the method with the Throwable at the end:

catch (Exception e){
            Log.d("MyTag", "exception ->:", e);
}

Log Api

Get line number in log handler

There is no LogRecord (JDK1.4 - JDK1.7) method to get the line number. If no thread handoff is occurring in your handler or upstream you can create a new Throwable().getStackTrace() and use the java.lang.StackTraceElement API to get the line number.

Example code can be found in the JavaMail API at MailLogger.inferCaller()/isLoggerImplFrame(). If you have to deal with thread handoffs, then you would have to log the line number as a log record parameter. Keep in mind that computing the callsite is expensive in terms of performance.

Dynamically get the current line number

I was able to use the Thread.currentThread().getStackTrace() method to create a set of functions that work together to produce the line number of the code that called the first method, like so:

/** @return The line number of the code that ran this method
 * @author Brian_Entei */
public static int getLineNumber() {
    return ___8drrd3148796d_Xaf();
}

/** This methods name is ridiculous on purpose to prevent any other method
 * names in the stack trace from potentially matching this one.
 * 
 * @return The line number of the code that called the method that called
 *         this method(Should only be called by getLineNumber()).
 * @author Brian_Entei */
private static int ___8drrd3148796d_Xaf() {
    boolean thisOne = false;
    int thisOneCountDown = 1;
    StackTraceElement[] elements = Thread.currentThread().getStackTrace();
    for(StackTraceElement element : elements) {
        String methodName = element.getMethodName();
        int lineNum = element.getLineNumber();
        if(thisOne && (thisOneCountDown == 0)) {
            return lineNum;
        } else if(thisOne) {
            thisOneCountDown--;
        }
        if(methodName.equals("___8drrd3148796d_Xaf")) {
            thisOne = true;
        }
    }
    return -1;
}

Hope this helps! I put these in a utility class so that they are out of the way, but still easily accessible. The second method is private to prevent any other method other than the first method from calling it so that it always works correctly.

Print current line number in intellij

One way to do this is to get the stack trace element and call getLineNumber.

public static int getCurrentLineNumber() {
    return Thread.currentThread().getStackTrace()[2].getLineNumber();
}

Note that I used an index of 2 because that refers to the frame of the method that calls getCurrentLineNumber. If you are just doing this inline, i.e. like this:

System.out.println(Thread.currentThread().getStackTrace()[1].getLineNumber());

You should use an index of 1 instead.

Note that an index of 0 refers to the frame of the getStackTrace method.

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