Intellij warning: Return value of the method is never used

I have some code that seems OK, but Intellij IDEA warns about many of its methods that return values that

Return value of the method is never used

Here is the actual code below, a builder class.

public static class StreamParserBuilder{    //optional - have defaults:    private long spanLimit1 = 2000L;    private long spanLimit2 = 100000L;    private long spanLimit3 = 3000000L;    private String[] coordinates = {"L1", "R2"};    private String outputDirectory = System.getProperty("user.dir");    private boolean isLastSteam = false;    //required from the builder.    private String[] args;    private String inputFile;    private String streamData;    private boolean isPaired;    public StreamParserBuilder(String[] args, String inputFile, String streamData, boolean isPaired){        this.args = args;        this.inputFile = inputFile;        this.streamData = streamData;        this.isPaired = isPaired;    }    public StreamParserBuilder withSpanLimit1(long spanLimit1){        this.spanLimit1 = spanLimit1;        return this;    }    public StreamParserBuilder withSpanLimit2(long spanLimit2){        this.spanLimit2 = spanLimit2;        return this;    }    public StreamParserBuilder withSpanLimit3(long spanLimit3){        this.spanLimit3 = spanLimit3;        return this;    }    public StreamParserBuilder withCoordinates(String[] coordinates){        this.coordinates = coordinates;        return this;    }    public StreamParserBuilder withOutputDirectory(String outputDirectory){        this.outputDirectory = outputDirectory;        return this;    }    public StreamParserBuilder isLastStream(boolean isLastSteam){        this.isLastSteam = isLastSteam;        return this;    }    public StreamParser build(){        return new StreamParser(this);    }

Is there an issue with the code, maybe i've instantiated the .build() method incorrectly? The code for my StreamParser constructor:

private StreamParser(StreamParserBuilder streamParserBuilder){    this.args = streamParserBuilder.args;    this.inputFile = streamParserBuilder.inputFile;    this.streamData = streamParserBuilder.streamData;    this.spanLimit1 = streamParserBuilder.spanLimit1;    this.spanLimit2 = streamParserBuilder.spanLimit2;    this.spanLimit3 = streamParserBuilder.spanLimit3;    this.coordinates = streamParserBuilder.coordinates;    this.outputDirectory = streamParserBuilder.outputDirectory;    this.isLastStream = streamParserBuilder.isLastSteam;    this.isPaired = streamParserBuilder.isPaired;}

Is there a better way to implement this? If the code is okay, what causes this warning?

Edit: Usage of the StreamParserBuilder, calling the withX functions:

 StreamParserBuilder streamBuilder = new StreamParserBuilder(args, inputFile, stream, isPaired); if (isSpanOneReplaced) streamBuilder.withSpanLimit1(spanLimit1); if (isSpanTwoReplaced) streamBuilder.withSpanLimit2(spanLimit2); if (isSpanThreeReplaced) streamBuilder.withSpanLimit3(spanLimit3); if (areCoordinatesReplaced) streamBuilder.withCoordinates(coordinates); if (isOutputDirectoryReplaced) streamBuilder.withOutputDirectory(outputDirectory); if (streamCount == streamData.size()) streamBuilder.isLastStream(true); StreamParser streamParser = streamBuilder.build();