from javax.swing import JTree
from javax.swing.tree import DefaultTreeCellRenderer, DefaultTreeModel, DefaultMutableTreeNode

class SampleTreeRenderer(DefaultTreeCellRenderer):
    def getTreeCellRendererComponent(self, tree, value, sel, expanded, leaf, row, hasFocus):
        print value
        return self

class SampleTreeModel(DefaultTreeModel): pass

tree = JTree()
tree.model = SampleTreeModel(DefaultMutableTreeNode()) 
tree.cellRenderer = SampleTreeRenderer()