How to reduce RAM usage in java?

Question

ReportDatabase class

public class ReportDatabase {

    private static final Map<String, Report> reportTypes;
    private static final String[] reportTypeNameVersion = {
            "Payroll Tax Report 1",
            "Capital Gains Tax Report 1",
            "Overall Expenditure Report 1",
            "Dark Costs Report 1",
            "Petty Cash Report 1",
            "Enron Fund Report 1",
            "COVID-19 Report 1",
            "COVID-20 Report 1",
            "Brawndo Investment Report 1",
            "Philanthropy Report 1",
            "Payroll Tax Report 2",
            "Capital Gains Tax Report 2",
            "Overall Expenditure Report 2",
            "Dark Costs Report 2",
            "Petty Cash Report 2",
            "Enron Fund Report 2",
            "COVID-19 Report 2",
            "COVID-20 Report 2",
            "Brawndo Investment Report 2",
            "Philanthropy Report 2"
    };

    static {
        reportTypes = new HashMap<>();

        for (String name: reportTypeNameVersion) {
            reportTypes.put(name, new ReportImpl(name.substring(0, name.length()-1), getReportCommission(), getReportData(), getReportData(), getReportData(), getReportData(), getReportData()));
        }
    }

    /**
     * Note from Tim:
     * The version number is entirely arbitrary and not used anywhere else, so we can't use it as a composite key...
     * There are also more than 2 versions per name in the full system.
     *
     * The recreation/copying here is simulating a networked database connection
     */
    public static Collection<Report> getTestReports() {

        Collection<Report> originals = reportTypes.values();
        List<Report> result = new ArrayList<>();

        for (Report original: originals) {
            result.add(new ReportImpl(original.getReportName(),
                    original.getCommission(),
                    original.getLegalData().clone(),
                    original.getCashFlowData().clone(),
                    original.getMergesData().clone(),
                    original.getTallyingData().clone(),
                    original.getDeductionsData().clone()));
        }

        return result;
    }

    private static double[] getReportData() {

        /*
        Note from Tim:
        If your machine's memory can't handle the whole product data, you could set this lower while you work out
        a way to stop the RAM explosion? We do need to be able to get at the whole product though.
        The database doesn't though...
         */

        double[] result = new double[500000];
        Random random = new Random();

        for (int i = 0; i < result.length; i++) {
            result[i] = random.nextDouble();
        }

        return result;
    }

    private static double getReportCommission() {
        Random random = new Random();

        return 1.0 + 99.0 * random.nextDouble();
    }
}

ReportImpl class:

import au.edu.sydney.cpa.erp.ordering.Report;

public class ReportImpl implements Report {

    private String name;
    private double commissionPerEmployee;
    private double[] legalData;
    private double[] cashFlowData;
    private double[] mergesData;
    private double[] tallyingData;
    private double[] deductionsData;

    public ReportImpl(String name,
                      double commissionPerEmployee,
                      double[] legalData,
                      double[] cashFlowData,
                      double[] mergesData,
                      double[] tallyingData,
                      double[] deductionsData) {
        this.name = name;
        this.commissionPerEmployee = commissionPerEmployee;
        this.legalData = legalData;
        this.cashFlowData = cashFlowData;
        this.mergesData = mergesData;
        this.tallyingData = tallyingData;
        this.deductionsData = deductionsData;
    }

    @Override
    public String getReportName() {
        return name;
    }

    @Override
    public double getCommission() {
        return commissionPerEmployee;
    }

    @Override
    public double[] getLegalData() {
        return legalData;
    }

    @Override
    public double[] getCashFlowData() {
        return cashFlowData;
    }

    @Override
    public double[] getMergesData() {
        return mergesData;
    }

    @Override
    public double[] getTallyingData() {
        return tallyingData;
    }

    @Override
    public double[] getDeductionsData() {
        return deductionsData;
    }

    @Override
    public String toString() {

        return String.format("%s", name);
    }
}

Method in a class, calling the method, getTestReports() from ReportDatabase class

public List<Report> getAllReports() {
        if (null == token) {
            throw new SecurityException();
        }

        return new ArrayList<>(ReportDatabase.getTestReports());
    }

For the above classes, I need to reduce the RAM usage and the rule is, I need to use ReportDatabase.getTestReports(), and I cannot modify anything in ReportDatabase class (only). If I print out the RAM consumption, it is around 450MB. I tried to create a ReportFactory class in order to apply a flyweight pattern, but I think that instantiating ReportDatabase class to use getTestReports directly takes around 400MB RAM consumption since:

There are 20 reports and each report has 6 double arrays. Each array has 500000 double numbers. If we calculate the memory, the double number in java is 8 bytes. And the total memory will be

8⋅500000⋅6⋅20/(1024⋅1024)≈450MB

How should I reduce the RAM usage for the above classes? Can I please get any hints?