Wrong thread for swing method invocation JAVA-W1062
Bug risk
Major
a year ago
—
a year old
show should be called from the event dispatch thread
80
81 Stage stage = (Stage) loginField.getScene().getWindow();
82 stage.setScene(scene);
83 stage.show(); 84 }
85
86 private String generateStudentNumber(){show should be called from the event dispatch thread
51
52 Stage stage = new Stage();
53 stage.setScene(scene);
54 stage.show(); 55 }
56
57 public void deleteCourse(ActionEvent actionEvent) {show should be called from the event dispatch thread
107
108 Stage stage = new Stage();
109 stage.setScene(scene);
110 stage.show();111 }
112
113 public void fillTree() {show should be called from the event dispatch thread
86
87 Stage stage = new Stage();
88 stage.setScene(scene);
89 stage.show(); 90 }
91
92 public void showFolderInfo(ActionEvent actionEvent) throws IOException {show should be called from the event dispatch thread
95
96 Stage stage = new Stage();
97 stage.setScene(scene);
98 stage.show(); 99 }
100}
Description
Methods show(), setVisible(), and pack() must not be invoked on the main thread.
With each invocation, these methods create the peer for the associated JFrame. Creation of the peer involves creation of the event dispatch thread.
At this point, the event dispatch thread could be in the middle of notifying listeners while show(), setVisible(), or pack() is still executing.
As a result, we could have two threads going through the Swing component-based GUI at the same time, which is a serious issue that might lead to deadlocks or other multithreading bugs.
Bad Practice
public void method() {
// These are problematic.
frame.show();
frame.setVisible(true);
frame.pack();
}
Recommended
Consider calling these methods on the event dispatch thread.
public void method() {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
frame.show();
frame.setVisible(true);
frame.pack();
}
}
}