Michael Olohan, 35, who was originally from Poppentree, in Ballymun, north Dublin, suffered fatal chest injuries during a row at a house at St Lawrence Road, Clontarf, at around 7.15am on Thursday.
The hostel is a HSE operated low-support independent living residence for people with mental health difficulties.
He was pronounced dead at the scene.
Gardai sealed off the area for a technical examination and appealed to the public for information.
Sean Murphy handed himself in to gardai on Thursday. He was arrested and detained at Clontarf Garda station for questioning.
Mr Murphy, who lived in an apartment at the same hostel as the deceased, was charged and brought to appear before Judge John Brennan at a late sitting of Dublin District Court this evening.
Dressed in a white T-shirt and black trousers, he sat at the side of the courtroom and spoke quietly to his solicitor Michael French before the case was called.
In evidence, Detective Sergeant Dave Ennis then told Judge Brennan the accused replied, “No, that is fine” when he was charged and cautioned.
He was then handed a copy of the charge sheet, the judge was told.
The district court does not have the jurisdiction to grant bail in a murder case.
Judge Brennan remanded Mr Murphy, who sat silently with his arms folded during the hearing, in custody to appear at Cloverhill District Court via video-link on Wednesday.
A book of evidence has to be prepared.
Mr French asked the court to request an “urgent psychiatric assessment” of his client in custody. Judge Brennan agreed to direct that he would receive the necessary psychiatric assessment.
He also granted him legal aid after noting the accused was in receipt of disability allowance.
