JSON.stringify(result) prints empty collection

Just recently when I did a simple test on my JQuery-mobile page to print the result return from JAX-RS end point, I received an empty collection.

It says

localhost:8080 says:

{"adjustmentInfo":[{}]}

At the same time, I am sure my end point returned a collection containing one AdjustmentInfo object.

Here is my AdjustmentInfo class.

// imports omitted

@XmlRootElement // don't forget, required by JAX-RS
public final class AdjustmentInfo implements Serializable {
    
    private long adjustmentNo;
    private String reason;
    private BigDecimal amount;
    private boolean negating;

    /**
     * Required by JAX-RS
     */
    private AdjustmentInfo() {
        this.adjustmentNo = 0;
        this.reason = null;
        this.amount = null;
        this.negating = false;
    }

    AdjustmentInfo(final Adjustment adjustment) {
        this.adjustmentNo = adjustment.getAdjustmentNo();
        this.reason = adjustment.getReason();
        this.amount = adjustment.getAmount();
        this.negating = adjustment.isNegating();
    }

    public long getAdjustmentNo() { ... }
    public String getReason() { ... }
    public BigDecimal getAmount() { ... }
    public boolean isNegating() { ... }
}

After trial-and-error, I found that apparently I had to implement all mutator method (I had not implemented it before because I didn’t have any need of them).

// imports omitted

@XmlRootElement // don't forget, required by JAX-RS
public final class AdjustmentInfo implements Serializable {
    
    private long adjustmentNo;
    private String reason;
    private BigDecimal amount;
    private boolean negating;

    /**
     * Required by JAX-RS
     */
    private AdjustmentInfo() {
        this.adjustmentNo = 0;
        this.reason = null;
        this.amount = null;
        this.negating = false;
    }

    AdjustmentInfo(final Adjustment adjustment) {
        this.adjustmentNo = adjustment.getAdjustmentNo();
        this.reason = adjustment.getReason();
        this.amount = adjustment.getAmount();
        this.negating = adjustment.isNegating();
    }

    public long getAdjustmentNo() { ... }
    public String getReason() { ... }
    public BigDecimal getAmount() { ... }
    public boolean isNegating() { ... }

    // IMPLEMENT THESE MUTATORS

    public void setAdjustmentNo(long adjustmentNo) { ... }
    public void setReason(String reason) { ... }
    public void setAmount(BigDecimal amount) { ... }
    public void setNegating(boolean negating) { ... }
}

Is it in the spec? I wonder…