Justice should not only be done, it should be seen to be done - and quickly, or revenge and resentment will fester. At the interpersonal level the main expression of 'mercy' is forgiveness. At the community level amnesty is an expression of the 'mercy' facet of reconciliation. Reconciliation efforts of mercy are often of a spiritual nature and therefore difficult to measure and monitor. It involves honesty, clarity, vulnerability, seeing each other face to face.
Truth can be a question of willingness to listen to each other's versions of history.
But it is also a part of a reconciliation process, which expresses itself in acknowledgement of injustice committed during violent conflict and oppression. And they can hopefully be used in any specific context to test whether peace and reconciliation being pursued is really holistic and comprehensive. But I will venture a few observations. Certainly justice does not yet prevail. There isn't even a consensus between the conflicting partners as to what constitutes justice for Jews as well as for Palestinians.