Can someone tell me where is the error in code on the bottom? I supose it's connected with startIndex and endIndex but I'm not sure and I don't know how to fix it.

All the time the same message: "Error in indicator: java.lang.NullPointerException"

I wanted to useichimoku indicator as a input of my own indicator, but first i wanted to check if it works, unfortunatelly it's not working

public IndicatorResult calculate(int startIndex, int endIndex) {
        //calculating startIndex taking into account lookback value
        if (startIndex - getLookback() < 0) {
            startIndex = getLookback();
        }
        if (endIndex + getLookforward() >= inputs[0][0].length) {
            endIndex = inputs[0][0].length - 1 - getLookforward();
        }
        if (startIndex > endIndex) {
            return new IndicatorResult(0, 0);
        }
                 
        ichi.setInputParameter(0, inputs[0]);  
        
        ichi.setOptInputParameter(0, timePeriod1);   
        ichi.setOptInputParameter(1, timePeriod2);
        ichi.setOptInputParameter(2, timePeriod3);
        
        ichi.setOutputParameter(0, outputs[0]);    
        ichi.setOutputParameter(1, outputs[1]);    
        ichi.setOutputParameter(2, outputs[2]);     
        ichi.setOutputParameter(3, outputs[3]);     
        ichi.setOutputParameter(4, outputs[4]);          
        
        ichi.calculate(startIndex, endIndex);        
                
        IndicatorResult ir = ichi.calculate(startIndex, endIndex);
        
        return ir;
    }

Try looking for details of NullPointerException in the 'logs' folder

where can I find 'logs' folder?

On windows: right click Jforex icon -> Properties ... check where it is installed. There should be subfolder named "logs"