How to prevent error recursive constructor invocation [duplicate]

Question

I can't find the solution. I'm using Java 11 and IntelliJ IDEA. Error is in line 10, only removing it gets rid of error, but I need this constructor.

The first time I encounter this error

public class Time2 {
    private int seconds;

    public Time2()
    {
        this(0);
    }

    public Time2(int hour)
    {
        this(hour*3600);
    }

    public Time2(int hour, int minute )
    {
        this(hour * 3600 + minute*60);
    }

    public Time2(int hour, int minute, int second)
    {

        if (hour < 0 || hour >= 24)
            throw new IllegalArgumentException("hour must be 0-23");

        if (minute < 0 || minute >= 60)
            throw new IllegalArgumentException("minute must be 0-59");

        if (second < 0 || second >= 60)
            throw new IllegalArgumentException("second must be 0-59");

        this.seconds = hour*3600 + minute*60 + second;
    }

    public Time2(Time2 time)
    {
        this(time.getHour(), time.getMinute(), time.getSecond());
    }

}

Answer 1

You have a recursive call between constructors:

public Time2() // A
{
    this(0);
}

public Time2(int hour) // B
{
    this(hour*3600);
}

public Time2(int hour, int minute ) // C
{
    this(hour * 3600 + minute*60);
}

public Time2(int hour, int minute, int second) // D
{

    if (hour < 0 || hour >= 24)
        throw new IllegalArgumentException("hour must be 0-23");

    if (minute < 0 || minute >= 60)
        throw new IllegalArgumentException("minute must be 0-59");

    if (second < 0 || second >= 60)
        throw new IllegalArgumentException("second must be 0-59");

    this.seconds = hour*3600 + minute*60 + second;
}

public Time2(Time2 time) // E
{
    this(time.getHour(), time.getMinute(), time.getSecond());
}

• A -> B
• B -> B
• C -> B
• D -> -
• E -> D

So for constructors A, B, C, they all call B, and from there on an endless recursive call occurs.

You must correct the C and B constructors:

public Time2(int hour, int minute ) // C
{
    this(hour, minute, 0);
}

public Time2(int hour) // B
{
     this(hour,0);
}

This way the endless recursiveness is avoided.

• A -> B
• B -> C
• C -> D
• D -> -
• E -> D

Also only in the last (D) constructor the conversion to seconds occur.

PS: You should use Java already existing API to convert to seconds (ex: Duration.ofHours(1).getSeconds()).