I’m getting the same output when using Observable.just vs Observable.from in the following case: I thought just was just supposed to emit a single item and from was to emit items in some sort of list. Whats the difference ? I also noted that just and from take only a limited amount of arguments. So Obse…
Tag: java
Restrict JTextField to only accept certain characters
I have 4 JTextFields that should only accept certain characters: binary digits (0, 1) octal digits, so (0 – 7) all digits (0 – 9) all hexadecimal characters (0 – 9, a – f, A – F) The user must not be able to input a forbidden character. I know how I could validate the input after…
How to map java.time.LocalDate field with Orika?
This occurs because LocalDate is not a JavaBean (it has no zero-arg constructor) To fix this, you need to create a LocalDateConverter : and then register it adding this line : As a shorcut, you can instead register the provided “PassThroughConverter” as suggested by Adam Michalik so Orika doesn…
Button setOnClickListener method is not invoked
The below is the sample code I’m trying to get the selected value from spinner on setOnClickListener method for the Button validateUser. Answer Toast needs to be shown. use .show() at the end. Toast.makeText(getApplicationContext(), “Button is Selected”, Toast.LENGTH_SHORT).show();
DynamoDB JsonMarshaller cannot Deserialize List of Object
I have a Java class which is the data-model of a table in DynamoDB. I want to use the DynamoDBMapper to save and load items from Dynamo. One member of the class is a List<MyObject>. So I used the JsonMarshaller<List<MyObject>> to serialize and de-serialize this field. The list can be success…
What does decoupling two classes at the interface level mean?
Lets say we have class A in package A and class B in package B . If object of class A has reference to class B, then the two classes are said to have coupling between them. To address the coupling, …
My JSch session doesn’t execute command
I’m trying to write a Java code that can ssh into a Unix server and reset a user’s password. So I tried to implement some of the code found in SO. Eg. Sending commands to remote server through ssh by Java with JSch Take commands(password) from string and set as InputStream to Unix servers in Java …
How to calculate a length of array with out using library
yesterday I appeared in interview,interviewer told me to write a code for calculating a length of array with out using a length property of Array class. For examaple- All answer given here are using String library. Answer
MIDI – MidiMessage Program Change with Instrument From Different Bank
The soundbank of the default synthesizer I’m using contains a variety of different instruments. For example, this code snippet… … prints the following: I can play an instrument from any of these banks through MidiChannel, the programChange method, and noteOn, like so (this plays instrument 1…
Preserve Java stack trace across threads
I am using ExecutorService to send mails asynchronously, so there is a class: That handles the sending. Any exception that gets caught is logged, for (anonymized) example: Not very helpful – I need to see the stacktrace that invoked the ExecutorService that caused all of this. My solution is to create a…